Tag: Production & Total Quality Management BMS Notes

Schedule repair jobs

During operations, LRUs that need repair are released to the repair shop and need to be repaired within the agreed planned lead time. This naturally leads to due-dates for repair jobs. The repair job scheduling function is to schedule the repair jobs subject to the resource constraints which are a consequence of the capacity dimensioning decision. Within these constraints, specific resources are assigned to specific repair jobs for specific periods in time so as to minimize the repair job tardiness. Additionally, the repair shop may batch repair jobs to use resources more efficiently by reducing set-up time and costs associated with using certain resources.

Maintenance planning can be defined as an end-to-end process that identifies and addresses any possible issues ahead of time. This involves identifying the parts and tools necessary for jobs and making sure they’re available and laid out in the appropriate areas, having a planner write out instructions on how to complete a job, and even determining and gathering the necessary parts and/or tools before a job is assigned. Maintenance planning also includes tasks related to parts like:

• Handling reserve parts
• Ordering nonstock parts
• Staging parts
• Illustrating parts
• Managing breakdowns and vendor lists
• Quality assurance (QA) and quality control (QC)

Maintenance planning should define the “what,” “why” and “how.” This means specifying what work needs to be done with what materials, tools and equipment; why a particular action was chosen (why a valve is being replaced instead of a seat); and how the work should be completed.

Maintenance scheduling refers to the timing of planned work, when the work should be done and who should perform it. It offers details of “when” and “who.” Scheduling is meant to:

• Schedule the maximum amount of work with the available resources
• Schedule according to the highest priority work orders
• Schedule the maximum number of preventive maintenance jobs when necessary
• Minimize the use of contract and outside resources by effectively using internal labor

When implemented together, maintenance planning and scheduling should have a significant benefit in multiple areas of your organization. These can include:

• Help with budgeting by controlling resources associated with maintenance
• A reduction in equipment downtime
• A reduction in spare parts
• Improved workflow
• Improved efficiency by minimizing the movement of resources between areas

Principles

• Job plans are needed for scheduling: Job plans should include the number of technicians required, the minimum skill level, work hours per skill level and information on job duration. Maintenance needs this information to schedule work, and job plans provide it in an efficient way. Does the job require welding? How many welders are needed? How many assistants does the engineer require? Asking questions like these during the creation of job plans helps determine scheduling requirements.
• Schedules and job priorities are important: The weekly schedule and the priorities that help determine this schedule are essential to improving productivity. Weekly scheduling frees up crew supervisors to focus on the current week without worrying about the backlog. Maintenance and operations use the weekly schedule for coordinating their tasks in advance, so it’s critical to properly determine the priority levels of new work orders to see if they should become part of the daily or weekly schedule.

Prioritizing advanced scheduling helps make sure sufficient workloads are assigned, which increases productivity and ensures critical work orders are completed first.

• Schedule based on the projected highest skills available: This principle states that a scheduler should develop a one-week schedule for each crew based on the available technician hours, the highest skill levels available, job priorities and details from the job plans. Schedulers should select a week’s worth of work from the plant backlog by using information on priority and job plan details. They should then use a forecast of the maximum capabilities of the technician crew for the coming week. After several weeks have passed, technicians should have a better idea about the amount of work they’re responsible for in a given week and become more productive.
• Schedule for every available work hour: Bringing the previous principles together, this guideline details how much work to schedule. The scheduler should assign work plans for the technicians to complete a task during the following week for 100 percent of the forecasted hours. So, if a crew has 800 labor hours available, the scheduler would give them 800 hours’ worth of work. Scheduling for 100 percent of the forecasted work hours prevents over- and under-scheduling.
• Daily work is handled by the crew leader: The crew leader or supervisor should develop a daily schedule based on the one-week schedule, current job progress and any new high-priority jobs that may arise. The supervisor should assign daily work to technicians based on skill level and work order requirements. In addition to the current days’ workload, the supervisor should handle emergencies and reschedule assignments as needed. Daily scheduling is almost always fluid thanks to the progress of the work being performed. This makes it difficult to schedule precise job times very far in advance. Inaccuracy of individual time estimates and reactive maintenance are the two biggest factors contributing to this issue.
• Measure performance with schedule compliance: Scheduling success is measured by the adherence to the one-week schedule and its effectiveness. Wrench time is the ultimate measure of workforce efficiency and planning and scheduling effectiveness. Planning work before assigning it reduces unnecessary delays, while scheduled work reduces delays between jobs.

Implement Maintenance Planning and Scheduling

Phase 1: Setup: This phase encompasses all the steps needed to ensure your organization is onboard with implementing maintenance planning and scheduling. You should have made your case to leadership by exposing the issue of low productivity, explaining how planning and scheduling can help solve that issue, calculating the value of productivity improvement, and presenting the results in the form of return on investment (ROI).

Phase 2: Define and analyze the situation: Phase two involves your team looking at your current situation and identifying problems currently faced in maintenance execution. During this phase, you should have representation from all levels of the maintenance process technicians, key managers or supervisors, and even representatives from procurement, finance and the warehouse. This workshop-like environment should outline the current maintenance planning and scheduling process.

Phase 3: Develop and prepare for delivery: Phase three involves planners and supervisors working to establish supporting documentation and process maps as well as defining in detail new processes, roles and responsibilities. You should also make any necessary changes to your computerized maintenance management system (CMMS) and develop training and coaching programs. Conducting a single overview training session followed by a role-specific training program is the most efficient way to go about training. This will prevent people from having to attend training sessions that don’t pertain to them.

Phase 4: Implement: Once everything is in place, it’s time to roll out the new maintenance planning and scheduling processes. The goal here is to embed the new standards and procedures into the daily routines of all those involved until they become the new normal. It’s generally accepted to allow for a three-month coaching period, where individuals are assessed and receive help to close any gaps in performance. If you operate a shift system, six months should be sufficient. Remember, planners should only work on the processes, not in the processes.

Phase 5: Review: This is sometimes called the “close-out” phase. Here, you want to ensure the new maintenance planning and scheduling process won’t disintegrate when the training and one-on-one time is over.

 Celebrate successes and make sure people are aware of how their hard work is paying off.

Review what is going well and what could be better, and document these for the next meeting with the planning department.

Develop sustainable procedures.

Phase 6: Sustain: This phase is considered “evergreen,” as processes and procedures should always be improving. Be sure you have:

• All performance metrics in place and review them in meetings, verifying that they are meeting long-term trends.
• Clearly defined procedures or job plans for each technician performing certain tasks.
• Ensure new technicians are properly trained on these job plans.
• Standardized, up-to-date and easily accessibly documentation in place.
• A set time for conducting process reviews to assess what is working and what isn’t. This is also the time to go over how processes can be improved.

Equipment reliability

The term equipment reliability and maintenance (ERM) encompasses not only equipment, such as machines, tools, and fixtures, but also the technical, operational, and management activities, ranging from equipment specifications to daily operation and maintenance, required to sustain the performance of manufacturing equipment throughout its useful life.

Reliability is a special attribute that describes the dependability of a component. This means that the component consistently performs a desired function under certain conditions for a certain period of time in order to meet business goals and customer needs. Theoretically, reliability can be described as:

Reliability = 1 – Probability of Failure

ERM affects drastically the three key elements of competitiveness quality, cost, and product lead time. Well-maintained machines hold tolerances better, help to reduce scrap and rework, and raise part consistency and quality. By increasing uptime and yields of good parts, ERM can reduce capital requirements, thereby cutting total production costs. It also can shorten lead times by reducing downtime and the need for retooling.

The replacement and displacement of conventional electro-mechanical factory equipment by mechatronic equipment have given rise to a very different set of reliability and maintenance requirements. The recent rush to embrace computer-integrated manufacturing (CIM) has further increased the use of relatively unknown and untested technology. The factory is becoming a web of interdependent subsystems, interconnected by computer controllers that communicate horizontally across peer processes and vertically to supervisory controllers above or slaves below. Much of the controller software was written with the assumption that all equipment works properly when, in fact, complicated and unpredictable failure modes, unanticipated by the system and equipment designers, are becoming increasingly apparent. It is seldom possible to predict how a system will fail when something somewhere in the plant breaks down. Because causal relationships are frequently hidden, repair is often time-consuming, expensive, and tedious. A better job of debugging these systems via simulation, analysis, and rapid development needs to be done.

Methods to Ensure Reliability of Equipment

Besides the engineering practices described above, there are three other essential components to equipment reliability: maintenance, inspection, and technology.

1) Maintenance

Maintenance can be divided into three categories, preventive, predictive, and corrective maintenance. Preventive measures are taken to eliminate unnecessary inspection and repair tasks. Predictive maintenance generally involves nondestructive inspection techniques to monitor the serviceability of the equipment. Corrective maintenance involves repairing or replacing components to restore equipment back to its operating conditions. Collectively, these tasks should be managed in a well developed reliability centered maintenance program.

2) Inspection

Nondestructive testing (NDT) techniques are used extensively throughout the lifecycle of equipment to locate and monitor damage mechanisms. Furthermore, inspection plays a major role in any equipment reliability program. Some common NDT methods used in the petroleum and chemicals industries include radiographic testing, ultrasonic testing, electromagnetic testing, and many more. When selecting an NDT method several considerations should be taken into account including the type of damage, where the damage is located (external or internal), and the size, shape, and orientation of the damage.

Additionally, there are two other types of inspection that provide information on the reliability and remaining life of equipment. These include risk-based inspection (RBI) and fitness-for-service (FFS) assessments. Put simply, the purpose of RBI is to identify and understand risk in order to reduce uncertainty about the condition of equipment. FFS assessments are performed to determine if a component is suitable for continued service.

Modern Scientific maintenance methods leverage advanced technologies, data analytics, and strategic approaches to enhance the reliability, efficiency, and cost-effectiveness of maintenance practices. These methods aim to move beyond traditional, time-based maintenance towards more proactive and data-driven strategies. Modern scientific maintenance methods leverage technology, data analytics, and strategic approaches to transform traditional maintenance practices. These methods enhance the proactive management of assets, reduce downtime, optimize resource utilization, and contribute to the overall efficiency and reliability of industrial processes. Implementing a combination of these methods based on specific organizational needs can lead to significant improvements in maintenance effectiveness and operational performance.

1. Predictive Maintenance:

Predictive maintenance utilizes data from sensors, machine learning algorithms, and historical performance data to predict when equipment is likely to fail. By analyzing real-time data, organizations can schedule maintenance activities just in time, reducing downtime and optimizing resource utilization.

Benefits:

• Minimized downtime.
• Reduced maintenance costs.
• Increased equipment reliability.

 

2. Condition-Based Maintenance:

Condition-based maintenance relies on real-time monitoring of equipment conditions using sensors and other measurement devices. Maintenance activities are triggered based on the actual state of the equipment, such as vibration levels, temperature, or fluid conditions.

Benefits:

• Targeted maintenance interventions.
• Increased asset lifespan.
• Improved resource efficiency.

 

3. Reliability-Centered Maintenance (RCM):

RCM is a systematic approach that identifies the most critical components of an asset and tailors maintenance strategies based on their importance to overall system reliability and performance. It involves analyzing failure modes and selecting the most effective maintenance tasks.

Benefits:

• Optimized maintenance efforts.
• Enhanced reliability.
• Improved cost-effectiveness.

 

4. Total Productive Maintenance (TPM):

TPM focuses on maximizing the efficiency and effectiveness of production processes by involving all employees in the maintenance and improvement of equipment and systems. It emphasizes a holistic approach to equipment management.

Benefits:

• Increased equipment effectiveness.
• Employee engagement in maintenance.
• Reduction in defects and breakdowns.

 

5. Root Cause Analysis (RCA):

Root cause analysis is a method used to identify the underlying causes of equipment failures or issues. It involves investigating incidents to determine the fundamental reasons for problems and implementing corrective actions to prevent their recurrence.

Benefits:

• Prevents recurring issues.
• Enhances problem-solving capabilities.
• Improves overall system reliability.

 

6. IoT-Based Maintenance:

The Internet of Things (IoT) is utilized to connect equipment and assets, enabling continuous monitoring and data collection. IoT sensors provide real-time insights into equipment performance, allowing for proactive maintenance based on actual usage patterns.

Benefits:

• Remote monitoring and diagnostics.
• Data-driven decision-making.
• Improved overall equipment effectiveness.

 

7. Augmented Reality (AR) Maintenance:

AR technologies overlay digital information onto the physical world, providing maintenance technicians with real-time guidance, visualizations, and instructions. This enhances troubleshooting, repairs, and training processes.

Benefits:

• Improved maintenance accuracy.
• Enhanced training and onboarding.
• Reduction in human errors.

 

8. Digital Twin Technology:

Digital twin technology creates virtual replicas of physical assets, allowing organizations to monitor and simulate their behavior. This enables predictive maintenance by analyzing the digital twin’s performance data.

Benefits:

• Simulation for predictive analysis.
• Early detection of potential issues.
• Improved decision-making.

 

9. Machine Learning in Maintenance:

Machine learning algorithms analyze large datasets to identify patterns and anomalies in equipment behavior. These algorithms can predict when maintenance is needed, optimize scheduling, and continually improve predictions over time.

Benefits:

• Enhanced predictive capabilities.
• Adaptability to changing conditions.
• Increased efficiency in decision-making.

 

10. Blockchain for Maintenance Management:

Blockchain technology is used to create transparent and secure maintenance records. It ensures the integrity of maintenance data, supports traceability, and facilitates the sharing of information across supply chains.

Benefits:

• Secure and transparent maintenance records.
• Enhanced traceability.
• Improved collaboration in supply chains.

Maintenance that is conducted in order to prevent failure. Usually this maintenance is planned some time in advance and has to be conducted within a registered time frame during which the asset is in non-operating condition

Preventative is used to maximise an assets useful lifetime and minimise cost. Its purpose is to avoid unscheduled or unplanned breakdowns, where reactive maintenance is used.

Preventive maintenance strategies can be further divided into usage and condition based maintenance. Under usage based maintenance, the total usage of a part is measured and maintenance is conducted when a certain threshold level has been reached. The usage of parts can be measured in many ways depending on the nature of the equipment. Time in the field is perhaps the most common mean to measure usage.

For vehicles (e.g., rolling stock), mileage is a common measure of usage. The number of on-off cycles is a measure of usage for equipment that is mainly loaded at the end or beginning of on-off cycles. For example, the number of landings is a measure of usage for the landing gear of an aircraft. Since the usage of equipment is usually scheduled, the moment that maintenance is performed can also be scheduled. If there is a large set-up cost associated with maintenance, it can be beneficial to interchange several parts simultaneously (Block replacement and/or overhaul). Otherwise, maintenance can be performed on a single component (Component replacement and/or overhaul).

Advantages:

Less risk factor: Because the equipment and your building are being regularly checked, they are at less risk to breaking down without notice. Therefore, creating a safer working environment for employees.

Follows a schedule: By following a schedule, you are able to keep to a budget while maintaining your building. Also, you will be able to keep track of all your equipment and pin point times when you will need to replace your equipment.

Longer equipment/building life: When equipment is being checked and maintained, it will be kept in its best shape, therefore extending its lifetime. With routine check-ups on building parts such as pipes, boilers, and roofing you’ll extend the life of your building as well.

Money saving: Over time, you will see that less money is being spend because you will not have to replace equipment as much, as well as dealing with last minute break downs. While there still may be some unplanned maintenance needed, the likely hood will go down when the building and equipment are regularly checked. Property wise, you’ll be able to catch roof leaks before they escalate and quickly repair them before mould and debris occur.

Less energy wasting: In general when equipment is not kept in the best conditions possible, it will drain more energy, hiking up your utilities bill. With properly maintained equipment, it will be saving you energy and money. While regularly kept lighting and cooling/heating systems will also help reduce the energy bill.

Less disruptions: With regular checks, you won’t be surprised when something goes wrong. It will be a quick fix because you will know what needs to be done. There will not be problems when it comes to closing down your property and disrupting your workers, if a large problem were to occur.

Disadvantages:

More money upfront: When initially starting a preventative maintenance plan, it will cost you more to regularly maintain equipment and the building, than it would be if you waited for things to simply break down.

Over maintenance: Because there is a regular plan, sometimes items may not need to be checked as often as planned. If this is the case, you can change your maintenance plan to checking the specific equipment or areas less often, while still maintaining a schedule.

More workers: Preventative maintenance require more workers because regular checks are a must. When compared to reactive maintenance, you simply need to call someone in for a onetime fix. Instead this method requires workers to always be on site and perform daily works.

Planned maintenance

Planned maintenance means that the organization is prepared for a breakdown and even expects it to happen. The equipment runs until it breaks, which initiates a run to failure (RTF) trigger. While RTF triggers can be unplanned, breakdown-maintenance plans use RTF as a way of lowering the cost of maintenance.

This kind of plan needs to be rigorously documented and controlled. Employees should be clear on exactly which parts will break down and which parts will be maintained normally via preventive maintenance. Without these checks, a breakdown maintenance plan can be exploited or run awry.

Unplanned breakdown maintenance

Unplanned breakdown maintenance, on the other hand, occurs when a piece of equipment fails or breaks unexpectedly also called an unplanned downtime event. While some facilities may not utilize a planned maintenance plan, nearly every facility needs resources in place for unplanned maintenance. After all, every piece of equipment will break or fault at some point in its life.

Condition-Based Maintenance

Condition-based maintenance is sometimes considered to be a more advanced alternative to preventive maintenance. Rather than being inspected according to a schedule, machines and systems are carefully observed for changes that could indicate upcoming failure.

With condition-based maintenance, technicians observe the system running and identify variables that could affect functioning, like temperature, vibration speed, power, the presence or absence of moisture, and more.

Corrective Maintenance

Corrective maintenance is initiated when a problem is discovered while working on another work order. With corrective maintenance issues are caught ‘just in time’.

For example, during a scheduled maintenance check or while fixing another issue, a maintenance technician notices that a pipe in a HVAC system is not working as it should. Corrective maintenance is then scheduled for a future date where the problem is repaired or replaced.

Pros

Failed equipment can lead to disastrous consequences, but a clearly-documented maintenance plan can actually have a few significant benefits for an organization.

• Minimizes maintenance cost by cutting out unnecessary preventive maintenance
• Lowers cost of replacing disposable items frequently (light bulbs, tools, fuses)
• Downtime for repairs is consolidated
• Low staffing needs
• Simple and easy to understand when maintenance is required

Cons

The downsides of breakdown-maintenance are especially important to weigh given the nature of the maintenance plan. For example, breakdown-maintenance should never be used with safety equipment because a single lapse can cost one or multiple employees their health or their lives.

• Form of waste in a manufacturing environment
• Safety issues can occur with unplanned failures
• Can be costly depending on parts that fail
• Requires careful planning and execution
• Can be difficult to pinpoint source of issues

Spares Planning and control

Spare Parts Management purpose is to provide “the right parts, in the right quantity, to the right place, at the right time, with the right level of quality, and at the least total cost to the organization”.

Effective management of maintenance spare parts is a critical contributor to equipment operating performance and to the cost of the maintenance investment.

The scope of Spare Parts Management therefore includes all functions from the supplier through to the point of use. identification and coding, criticality classification, procurement, quality inspection, stocking policies, links to work planning (kitting, staging), supplier management and internal performance.

For managing parts inventory more effectively:

Identify all spare parts: Make sure that all parts required for maintaining the asset are properly identified. If, for example, a part is required for a major overhaul, there may be several items that are purchased for a one-time use. Once the machinery overhaul is completed, there may be unused parts which have future use and should be inventoried. Other equipment in the plant may be able to use the same parts. So, rather than maintenance storing these parts without any correlation with the asset, the items should be added to the inventory control system and placed into parts inventory on the EAMS/CMMS.

Classify all spare parts: Classify the spare parts as per criticality. This classification will support the process to define an effective safety stock:have the right parts, at the right time, with the lowest possible cost at the minimum inventory value.

Utilize and Manage the Bill of Materials (BOM): Having accurate BOMs will support the scheduled preventive maintenance (PM) that is needed on a given piece of equipment. This process will allow the generation of a work order with the scheduled date of the PM.

BOMs will make ordering parts and placing work orders simpler. Additionally, make sure that your BOMs are kept up to date, considering the asset status and modifications.

Use the work order: All spare parts that have been used have to be linked to a work order. For PM, work orders requested in advance can be pulled and staged for pickup or delivered to the requesting department. This will reduce the maintenance department’s wait time at the parts warehouse for their work order to be fulfilled. Work orders need to be created for all parts issuance so that inventory remains accurate.

In case of emergency, it would be possible to understand the historical information related to breakdowns to improve the parts in stock, when this is reasonable.

Limited access to the parts warehouse inventory: Limiting access to the parts warehouse inventory is mandatory to maintain inventory accuracy. Adopt a policy that parts inventories are “off limits” and only parts department employees have access, utilizing badge access to entry and exit points. Allowing everyone to have access can quickly make parts inventories inaccurate.

Optimize the warehouse: Centralize and consolidate parts – Having all your parts centralized (in one or satellite warehouses) and consolidated can make security easier but also makes this potentially large asset easier to control and maintain inventory accuracy.

Use an Inventory control system: By utilizing your ERP’s warehouse functionality or a warehouse management system (WMS) to manage your parts inventory will ensure accuracy and ease of managing your parts warehouse. This should be linked to the EAMS/CMMS.

Using barcodes and scanning functionality in conjunction with the system will improve the efficiency of the management processes in the parts warehouse and inventory accuracy.

Define a stock location for every part: Ensure that stock locations are created at the lowest detail, typically a bin and slot location for each SKU, allowed by your systems.

Implement cycle counting for inventory control: Cycle Counting is a Periodic inventory system audit-practice in which different portions of an inventory are counted or physically checked on a continuous schedule, related with inventory ABC classification. The usual class breakpoints applied are:

A = 10% of line items, gives 65% of turnover

B = 20% of line items, gives 25% of turnover

C = 70% of line items, gives 10% of turnover

Each portion is counted at a definite, preset frequency to ensure counting of each item at least once in an accounting period.

Some variation about these figures is usual, but significant differences can indicate problems with stock holding policy.

Standardize Spare Parts: Standardizing for spare parts management, usually means agreeing that a certain type/model of equipment will be used and with that the spare parts required for each installation will be the same. This is different to industry-wide standardization. This can contribute to improve the MTTR, the negotiations with the Spare Parts Suppliers and the stocks.

Develop Spare Parts Management Processes: Make sure that your Spare Parts Management Processes are developed as per best practices to ensure sustainability and a base for training.

Decide based on accurate data: Use quality data for decision making: develop your reports and KPI´s considering the Spare Parts Management Processes, to support the improvement and base for Spare parts maintenance budget.

Benefits of spare parts management:

• Allows you to keep spare inventory levels low, reducing carrying and storage costs but providing access to spare parts when needed.
• Better service to your customers. The longer your operations are up and running, the better you’re able to deliver the services and support your customers demand.
• Enhanced part visibility so your supply chain can show where the need is and where the parts are headed.
• Improved equipment uptime as you limit how long equipment is down and don’t have to wait to generate revenue or find a funding source to repair a part when it breaks.
• Quicker repairs and replacements for defective parts, plus assistance with larger failures.

Waste management places an important role in managing operations. Wastes can be categorized into obsolete, surplus and scrap items.

• Obsolete items: These are those materials and equipments which are not damaged and which have economic worth but which are no longer useful for the Company’s operation owing to many reason such as, changes in product line, process, materials, and so on.
• Surplus items: These are those materials and equipments which have no immediate use but have accumulated due to faulty planning, forecasting and purchasing. However, they have a usage value in future.
• Scrap: It is defined as process wastage, such as, turnings, borings, sprues and flashes. They may have an end-use within the plant having commercial values. Hence, should be disposed of periodically.

Disposal of Scrap surplus and Obsolete materials

Disposal of scrap when handled in an imaginative manner can result in handsome returns to the organization. An effective disposal requires a compact disposal organization reporting to the materials manager, continuous market survey on the prices of various categories of scrap generated in the plant and constant touch with the industries which generate similar scrap and with the end-users.

Disposal action follows when the scrap cannot be utilized within the organization. In practice, it has been found that it is profitable to dispose the scrap directly to end-users rather than to middlemen who normally form a cartel of their own which leads to lower returns. Before disposal action it is essential that the scrap is segregated according to metal, size, etc. when the scrap is mixed, the return is even lower than the lowest element in the mixture. This is because the buyer of scrap will have to segregate it at an extra cost. A cursory analysis of scrap prices will reveal that sheet and plate cuttings will fetch fewer amounts per a tonne compared to that of turnings and borings. Also when costly scrap such as copper, aluminum and tungsten are involved, it is imperative that they are segregated as returns are huge and price levels are different. Since scrap is generated process-wise, it comes out in a segregated condition and there should be no difficulty in sorting.

Auction and Tender methods are frequently used for disposal of scrap. Parties in both the cases are normally required to inspect the scrap in the scrap yard and deposit earnest money. Very often the company insists on a basic price depending upon the category of scrap. The disposal section works, in this aspect, in close coordination with the finance department. In many cases the disposal section may try to enter into a long-term contact with end-users such as steel plants.

Many companies have found to their displeasure scrapped components appearing in the market and competing with their parts as ‘original equipment’. This is the price which organizations pay for not dismantling and disfiguring the scrap before disposal. Automobile spare parts and bearings especially are prone to such dangers. For this purpose some organizations go to the extent of requesting vehicle users to demolish filters and plugs before scrapping them. This is very important aspect.

In view of the paucity of raw materials and shortage of credit, it is necessary that optimum usage of materials is made and funds tied up in obsolete surplus and scrap items minimized. This is only possible when top management shows commitment and support. The employees of the organizations are naturally the best people to suggest improvements in materials, processes and new end users for scrap. It is they who can minimize the accumulation of scrap through coordination.

Therefore, top management should work out formal reward systems to promote employee participation in this matter. A few organizations have suggestion box schemes which pay rich dividends to the organization. Employees, too get rewards and recognition in the process.

Following are the reasons for the generation and accumulation of obsolete, surplus and scrap items:

• Changes in product design: This may lead to some items getting invalid so far as the final product is concerned. Hence, the entire stock of such items as surplus obsolete.
• Rationalization: Sometimes raw materials are renationalized so as to minimize variety and simplify procurement. The rationalization process renders some items as surplus or obsolete.
• Cannibalization: When a machine breakdown occurs, sometimes it is rectified using parts of an identical machine which is not functioning due to various reasons. This process of ‘cannibalization’ is not uncommon in many project-based industries. When continued unchecked, this results in obsolete and scrap items.
• Faulty planning and forecasting: The marketing department may have projected a sales forecast which might be on the higher side. Any material planning has to be based on sales forecasts and this could result in surplus items. Wrong indenting by the user departments also leads to accumulation.
• Faulty purchase practices: Sub-optimizing decisions like buying in bulk to take care of discounts and transportation economy without taking into account factors such as, shelf life, storage space requirements and technological changes once again lead to the accumulation of surplus and obsolete stocks.
• Other causes: Many items are held as insurable spares for many years without any consumption. Faulty store-keeping methods, without adequate preservation, lead to spoilage. Inferior materials handling, improper codification and poor manufacturing methods also result in obsolete, surplus and scrap items. Poor maintenance of machine tools may result in excessive tools wear and greater process scrap.

Production planning is the planning of production and manufacturing modules in a company or industry. It utilizes the resource allocation of activities of employees, materials and production capacity, in order to serve different customers.

Different types of production methods, such as single item manufacturing, batch production, mass production, continuous production etc. have their own type of production planning. Production planning can be combined with production control into production planning and control, or it can be combined with enterprise resource planning.

Production planning is the future of production. It can help in efficient manufacturing or setting up of a production site by facilitating required needs. A production plan is made periodically for a specific time period, called the planning horizon. It can comprise the following activities:

• Determination of the required product mix and factory load to satisfy customer’s needs.
• Matching the required level of production to the existing resources.
• Scheduling and choosing the actual work to be started in the manufacturing facility”
• Setting up and delivering production orders to production facilities.

Types of planning

Different types of production planning can be applied:

• Advanced planning and scheduling
• Capacity planning
• Master production schedule
• Material requirements planning
• MRP II
• Scheduling
• Workflow

Tips to improve production planning

Forecasting demand

Before production planning, the first action to take is forecasting demands for your products. While this may not be accurate to the last digit, getting rough estimates rolling is important to allocate resources. Forecasting can be done based on factors like historical order data and market trends/demands. Drawing out proper forecasts helps planning the type and quantity of materials to be produced and also the planning of raw material procurement.

Control inventory

Both, inventory shortage and inventory surplus are undesirable states. You can’t proceed with production when there’s a shortage and you waste space and money when there’s a surplus. Efficiently controlling inventory involves reordering when current inventory dips below a certain level, calculating the lead times to order items with long lead times earlier, and factoring in storage conditions. A well-controlled raw material inventory helps run a smooth production line and outputs finished goods inventory on time.

Plan for everything and everyone

Often, when making production plans, some machine or some person is unaccounted for. The problem here is that that machine may go down or the worker may be on leave, or worse, working on something else. Hence, plan for every machine, raw material, workstation, warehouse, and employee.

Monitor

Once the production plan is final and work orders are handed out, the manufacturing process begins. At this point, things may go wrong, machines pause, or items may get misplaced. Constantly monitoring the factory floor with supervisors or with IoT devices ensures that all the pieces are moving as planned.

Adapt

Despite your best planning, things go wrong on the factory floor. Anything can happen from suppliers making late deliveries to workers falling sick to machines failing. It’s important to be flexible and adapt to these changes quickly so that the planned quantities can be delivered on time. Ideally, you should also plan for any such risks beforehand.

KPIs for production planning

A few key performance indicators to track in production planning are:

• Production cost: This is essentially the monetary cost involved in producing the item. Costs include raw materials, electricity, fuel, worker salaries, rent, etc.
• Capacity utilization rate: It’s the percentage of actual manufacturing output against the total possible manufacturing output. If many machines and workers are sitting idle, your capacity utilization is low. Ideally, you want it high but never full.
• Projected versus actual hours: When planning, you may allocate a certain number of hours for completion of the production plan. But, it may take longer due to delays from workers or unexpected tasks. This KPI gives you a picture of how much time it was supposed to take and how much it did.
• Employee utilization (productivity): You want workers to be working properly during the punch in and punch out. Nobody wants to be a machine by working to the dot but working 4 hours out of 8 is also not reasonable.
• Takt time: Takt time is a lean manufacturing concept. It is the time taken to produce a single unit of item.

Acceptance sampling is a statistical measure used in quality control. It allows a company to determine the quality of a batch of products by selecting a specified number for testing. The quality of this designated sample will be viewed as the quality level for the entire group of products.

A company cannot test every one of its products. There may simply be too high a volume or number of them to inspect at a reasonable cost or within a reasonable time frame. Or effective testing might result in the destruction of the product or making it unfit for sale in some way.

Acceptance sampling solves these problems by testing a representative sample of the product for defects. The process involves first, determining the size of a product lot to be tested, then the number of products to be sampled, and finally the number of defects acceptable within the sample batch.

Products are chosen at random for sampling. The procedure usually occurs at the manufacturing site the plant or factory and just before the products are to be transported. This process allows a company to measure the quality of a batch with a specified degree of statistical certainty without having to test every single unit. Based on the results how many of the predetermined number of samples pass or fail the testing the company decides whether to accept or reject the entire lot.

The statistical reliability of a sample is generally measured by a t-statistic, a type of inferential statistic used to determine if there is a significant difference between two groups that share common features.

Acceptance sampling uses statistical sampling to determine whether to accept or reject a production lot of material. It has been a common quality control technique used in industry. It is usually done as products leaves the factory, or in some cases even within the factory. Most often a producer supplies a consumer a number of items and a decision to accept or reject the items is made by determining the number of defective items in a sample from the lot. The lot is accepted if the number of defects falls below where the acceptance number or otherwise the lot is rejected.

In general, acceptance sampling is employed when one or several of the following hold:

• Testing is destructive;
• The cost of 100% inspection is very high; and
• 100% inspection takes too long.

A wide variety of acceptance sampling plans are available. For example, multiple sampling plans use more than two samples to reach a conclusion. A shorter examination period and smaller sample sizes are features of this type of plan. Although the samples are taken at random, the sampling procedure is still reliable.

Acceptance sampling for attributes

A single sampling plan for attributes is a statistical method by which the lot is accepted or rejected on the basis of one sample. Suppose that we have a lot of size M; a random sample of size  N<M is selected from the lot; and an acceptance number B is determined. If it is found the number of nonconforming is less than or equal to B, the lot is accepted; and if the number of nonconforming is greater than B, the lot is not accepted. The design of a single sampling plan requires the selection of the sample size N and the acceptance number B.

MIL-STD-105 was a United States defense standard that provided procedures and tables for sampling by attributes (pass or fail characteristic). MIL-STD-105E was cancelled in 1995 but is available in related documents such as ANSI/ASQ Z1.4, “Sampling Procedures and Tables for Inspection by Attributes”. Several levels of inspection are provided and can be indexed to several AQLs. The sample size is specified and the basis for acceptance or rejection (number of defects) is provided. MIL-STD-1916 is currently the preferred method of sampling for all Department of Defense (DoD) contracts.

O.C. curves quantifies manufacturer’s (producer’s) risk and consumer’s (purchaser’s) risk. This is a graph of the percentage defective in a lot versus the probability that the sampling plan will accept a lot.

An O.C. Curve drawn for sampling plan of n = 300 and C = 10 at Fig. 60.1 indicates the following:

AQL = 0.02 or 2%

Manufacturer’s risk = 0.05

Consumer’s risk = 0.10

LTPD = 0.05 or more defectives.

All practical sampling plans have an operating characteristics curve, briefly called O.C. curve.

Following points need emphasis regarding O.C. curves:

(i) There is some chance that good lots will be rejected.

(ii) There is some chance that bad lots will be rejected.

(iii) These risks can be calculated by the theory of probability and depends on the number of samples inspected, the acceptance number, and the percent defectives in the lot offered for sample inspection. Given the amount of risks which can be tolerated, a sampling plan can be devised to meet these requirements.

(iv) The larger the sample used for inspection, the nearer the O.C. curve approaches the ideal. However beyond a certain point, the added cost in inspecting a large number of parts far exceeds the benefit derived.

In any acceptance sampling plan, three parameters are specified. The first parameter is number of articles N in the lot from which sample is to be drawn. The second parameter is the number of articles n in the random sample drawn from the lot, and the third is the acceptance number C.

This acceptance number C is the maximum allowable number of defective articles in the sample. If more than C defectives are found in a sample the lot is liable to be rejected. Since the lot size has little affect on the probability of acceptance, therefore lot size is generally ignored in deriving a sampling plan.

O.C. curve of an acceptance sampling plan (i.e. for a particular combination of n and C) shows how well the sampling plan discriminates between good and bad lots. In order to exam­ine the suitability of an acceptance sam­pling plan, it is necessary to compare their performance over a range of pos­sible quality levels of the product.

The graph of this performance is known as operating characteristic curve. Fig. 60.2 below shows an ideal O.C. curve where it is desired to accept all lots having 3% or less defectives, and to reject all lots having more than 3% defectives.

In this curve, all lots with less than 3% defectives have a probability of accep­tance of 100%, while all lots with more than 3% defectives have a probability of acceptance as 0%. However, such a plan does not exist in reality.

Zones of O.C. Curve:

O.C. curve can be divided into following 3 zones:

(a) Acceptance Zone:

In this zone all the batches are accepted, therefore, the O.C. curve should be so selected that its acceptance zone accepts what is considered to be satisfactory lot.

(b) Rejection Zone:

In this zone, all the batches are rejected. Hence the O.C. curve selected should be such that it rejects what is considered to be an unsatisfactory lot.

(c) Zone of Indecision:

This is the zone where there is no purity that whether any particular batch or lot will be accepted or rejected. This problem can be solved either by adopting 100% inspection or by taking larger sample, but these will increase the inspection costs.

A batch or lot in this zone is worse than acceptable lot, and better than those what is considered as unaccept­able. Thus its quality is border-line, and practically does not matter much whether a lot is finally accepted or rejected from this zone.

Credit: https://www.businessmanagementideas.com/production-management/operating-characteristic-o-c-curves/6960

Availability of Raw Materials:

Proximity of sources of raw materials is the obvious explanation of the location of majority of sugar mills in Uttar Pradesh. This means that the raw material should be available within the economical distance. Easy availability of supplies required for maintenance and operation of the plant should also be considered.

Proximity to Markets:

Cost of distribution is an important item in the overhead expenses. So it will be advantageous to be near to the center of demand for finished products. Importance of this is fully realized if the material required for the manufacturing of products are not bulk and fright charges are small.

Transport Facilities:

Since freight charges of raw materials and finished goods enter into the cost of production, therefore transportation facilities are becoming the governing factor in economic location of the plant. Depending upon the volume of the raw materials and finished products, a suitable method of transportation like rail, road, water transportation (through river, canals or sea) and air transport is selected and accordingly plant location is decided. Important consideration should be that the cost of transportation should remain fairly small in comparison to the total cost of production.

Location in Proximity of Cities:

First tendency is to locate the industries or enterprises in the proximity of cities rather than in rural or urban areas. These sub-urban sites offer today practically all advantages, facilities and services available in cities and towns with the added advantage of land required for future expansion on cheap rates.

Planned Industrial Centres:

While industrial towns may be planned and developed by big industrial houses or govt., the late trend is to develop areas as industrial estates and sell these to people interested in starting their units at various places. Noida and Faridabad are the examples of this type of development.

Competition for Development of Industries:

In order to generate the employment opportunities the state and central govt. offer concessions to attract industrialists to set up industries in their states or territories.

Appropriate Site Selection:

Appropriate site selection is important because of the following:

(i) A good location may minimize the cost of production and distribution to a considerable extent. Such reduction in the cost of production helps in elevating either the competitive strength or the profit margin of the business.

(ii) Initiation of an enterprise involve a relatively large permanent investment. If the selected site is not proper, all the money invested on factory building, installation of machinery etc. will go waste and the owner will have to suffer a great loss.

(iii) Location put constraints for the physical factors of the overall plant designs heating, ventilation requirements, storage capacity for raw materials, transportation requirements for input material and finished products, energy requirements cost of labour, taxes and construction costs.

(iv) Location of plant decides the nature of investment cost to be incurred.

(v) Government policies sometimes play an important role in site selection.

(vi) Probably no location is so perfect as to guarantee success but locations can be so bad as to bankrupt an enterprise.

Nearness to Markets:

It reduces the cost of transportation as well as the chances of the finished products getting damaged and spoiled in the way (especially perishable products). Moreover a plant being near, to the market can catch a big share of the market and can render quick service to the customers.

Availability of Labour:

Stable labour force, of right kind, of adequate size (number), and at reasonable rates with its proper attitude towards work are a few factors which govern plant location to a major extent. The purpose of the management is to face less boycotts, strikes or lockouts and to achieve lower labour cost per unit of production.

Availability of Fuel and Power:

Because of the wide spread use of electric power, in most cases fuel (coal, oil, etc.) has not remained a deciding factor for plant location. Even then steel industries are located near source of fuel (coal) to cut down the fuel transportation costs.

It is of course essential that electric power should remain available continuously, in proper quantity and at reasonable rates.

Availability of Water:

Water is used for processing, as in paper and chemical industries, and is also required for drinking and sanitary purposes. Depending upon the nature of plant, water should be available in adequate quantity and should be of proper quality (clean and pure). A chemical industry should not be set up at a location which is famous for water shortage.

Climatic Conditions:

With the developments in the field of heating, ventilating and air- conditioning, climate of the region does not present much problem. Of course, control of climate needs money.

Financial and Other Aids:

Certain states give aids as loans, feed money, machinery, built up sheds, etc., to attract industrialists.

Land:

Topography, area, the shape of the site, cost, drainage and other facilities, the probabil­ity of floods, earthquakes (from the past history) etc., influence the selection of plant location.

Community Attitude:

Success of an industry depends very much on the attitude of the local people and whether they want work or not.

(11) Presence of related industries.

(12) Existence of hospitals, marketing centres, schools, banks, post offices, clubs, etc.

(13) Local bye-laws, taxes, building ordnances, etc.

(14) Housing facilities.

(15) Security.

(16) Facilities for expansion.

The Organization of physical facilities involves careful planning and management of various aspects to create a safe, comfortable, and efficient environment. The organization of physical facilities requires a holistic approach, considering the interplay of various elements to create a harmonious and functional environment. Regular assessments, maintenance, and updates are essential to adapt to evolving needs and ensure the ongoing safety and well-being of occupants. Collaboration between facility managers, architects, health and safety professionals, and technology experts is crucial for effective facility organization.

Building Design:

• Space Planning

Efficient space planning ensures optimal use of available space for different functions within the facility. Consideration is given to workspaces, storage, common areas, and circulation paths.

• Architectural Design

Architectural elements contribute to the overall aesthetics and functionality of the building. This includes the layout of rooms, entrances, exits, and the overall design style.

• Accessibility

Design should comply with accessibility standards to ensure that the facility is inclusive and accessible to individuals with disabilities. This involves considerations for ramps, elevators, and accessible restrooms.

• Flexibility

Building design should allow for flexibility to accommodate future changes and expansions in operations or technology. Modular layouts and adaptable spaces contribute to flexibility.

Sanitation:

• Hygiene Standards

Maintaining high hygiene standards is crucial for the health and well-being of occupants. Sanitary facilities, including restrooms and kitchens, must be regularly cleaned and stocked with necessary supplies.

• Waste Management

Proper waste disposal and recycling facilities should be in place. Waste bins should be strategically located, and recycling programs can contribute to sustainability efforts.

• Cleaning Protocols

Establishing and enforcing cleaning protocols ensures that all areas of the facility are regularly cleaned. This includes floors, surfaces, common areas, and high-touch surfaces.

Lighting:

• Natural Lighting

Incorporating natural lighting through windows and skylights helps reduce reliance on artificial lighting. It also contributes to a positive and energizing environment.

• Artificial Lighting

Adequate and well-designed artificial lighting is essential, especially in areas with limited natural light. It should be evenly distributed to prevent glare and shadows.

• Energy Efficiency

Using energy-efficient lighting solutions, such as LED bulbs, can contribute to cost savings and environmental sustainability. Motion sensors and programmable lighting systems enhance efficiency.

Air Conditioning and Ventilation:

• Temperature Control

Maintaining a comfortable temperature is crucial for occupant well-being. Heating, ventilation, and air conditioning (HVAC) systems should be properly maintained and calibrated.

• Air Quality

Ensuring good indoor air quality involves proper ventilation to bring in fresh air and remove pollutants. Regular maintenance of HVAC systems, air filters, and ducts is essential.

• Energy Efficiency

Energy-efficient HVAC systems contribute to cost savings and environmental sustainability. Smart controls and zoning systems allow for targeted temperature control in different areas.

Safety:

• Emergency Exits

Clearly marked and unobstructed emergency exits are essential for quick and safe evacuation in case of emergencies. Exit routes should be regularly reviewed and communicated to occupants.

• Fire Safety

Fire safety measures include the installation of fire alarms, fire extinguishers, and sprinkler systems. Regular fire drills and training sessions ensure that occupants know how to respond in case of a fire.

• Security Systems

Implementing security systems, such as access control and surveillance cameras, enhances the safety of the facility. Security personnel and protocols contribute to a secure environment.

• First Aid Stations

First aid stations with necessary medical supplies should be strategically located. Trained personnel should be available to administer first aid in case of injuries.

• Compliance with Regulations

The facility should comply with building codes, safety regulations, and occupational health standards. Regular inspections and audits help ensure ongoing compliance.

Workplace Ergonomics:

• Ergonomic Furniture

Providing ergonomic furniture and workstations contributes to the well-being and productivity of employees. Adjustable chairs, desks, and computer stations help prevent musculoskeletal issues.

• Workspace Layout

Efficient layout design considers the placement of workstations, equipment, and common areas to support smooth workflows and minimize physical strain on employees.

Signage and Wayfinding:

• Clear Signage

Clear and visible signage helps occupants navigate the facility easily. This includes directional signs, room labels, and safety signs indicating exits and emergency procedures.

• Wayfinding Systems

Implementing wayfinding systems, especially in large facilities, assists visitors and employees in finding their way around. Maps and digital wayfinding tools can enhance navigation.

Technology Integration:

• Smart Building Systems

Integrating technology into the facility can enhance efficiency and safety. Smart building systems can control lighting, HVAC, security, and other aspects through automated and remotely accessible systems.

• Communication Tools

Implementing communication tools, such as intercoms, emergency notification systems, and digital displays, enhances information dissemination in the facility.

Sustainability Practices:

• Energy Conservation

Implementing energy conservation measures, such as energy-efficient appliances and lighting, contributes to sustainability goals and cost savings.

• Water Conservation

Installing water-efficient fixtures and implementing water conservation practices helps reduce water consumption and promotes environmental responsibility.

• Green Spaces

Incorporating green spaces, indoor plants, and sustainable landscaping contributes to a healthier environment and improved air quality.

Collaboration Spaces:

• Designing Collaborative Areas

Creating collaborative spaces within the facility supports teamwork and creativity. These areas can include meeting rooms, open workspaces, and common areas designed for collaboration.

• Technology in Collaboration Spaces

Equipping collaboration spaces with technology, such as video conferencing tools and interactive displays, enhances communication and collaboration among teams.

Accessibility for People with Disabilities:

• Accessibility Features

Facilities should include features such as ramps, elevators, and accessible restrooms to ensure that individuals with disabilities can navigate the space independently.

• Compliance with Accessibility Standards

Compliance with accessibility standards, such as the Americans with Disabilities Act (ADA), is essential to create an inclusive environment.

Occupancy Planning:

• Optimizing Space Utilization

Regularly reviewing and optimizing space utilization ensures that the facility meets the changing needs of the organization. This may involve reconfiguring workspaces or expanding certain areas.

• Occupancy Limits

Establishing and communicating occupancy limits for different areas helps maintain a comfortable and safe environment. This is especially important in shared spaces and during emergencies.

Factory Building

Factory building is a factor which is the most important consideration for every industrial enterprise. A modem factory building is required to provide protection for men, machines, materials, products or even the company’s secrets. It has to serve as a part of the production facilities and as a factor to maximize economy and efficiency in plant operations. It should offer a pleasant and comfortable working environment and project the management’s image and prestige. Factory building is like skin and bones of a living body for an organization. It is for these reasons that the factory building acquires great importance.

Following factors are considered for an Industrial Building:

• Design of the building
• Types of buildings

Lighting

It is estimated that 80 per cent of the information required in doing job is perceived visually. Good visibility of the equipment, the product and the data involved in the work process is an essential factor in accelerating production, reducing the number of defective products, cutting down waste and preventing visual fatigue and headaches among the workers. It may also be added that both inadequate visibility and glare are frequently causes accidents.

In principle, lighting should be adapted to the type of work. However, the level of illumination, measured in should be increased not only in relation to the degree of precision or miniaturization of the work but also in relation to the worker’s age. The accumulation of dust and the wear of the light sources cut down the level of illumination by 10–50 per cent of the original level. This gradual drop in the level should therefore be compensated for when designing the lighting system. Regular cleaning of lighting fixture is obviously essential.

Excessive contrasts in lighting levels between the worker’s task and the general surroundings should also be avoided. The use of natural light should be encouraged. This can be achieved by installing windows that open, which are recommended to have an area equal to the time of day, the distance of workstations from the windows and the presence or absence of blinds. For this reason it is essential to have artificial lighting, will enable people to maintain proper vision and will ensure that the lighting intensity ratios between the task, the surrounding objects and the general environment are maintained.

Control of Lighting

In order to make the best use of lighting in the work place, the following points should be taken into account:

• For uniform light distribution, install an independent switch for the row of lighting fixtures closest to the windows. This allows the lights to be switched on and off depending on whether or not natural light is sufficient.
• To prevent glare, avoid using highly shiny, glossy work surfaces.
• Use localized lighting in order to achieve the desired level for a particular fine job.
• Clean light fixtures regularly and follow a maintenance schedule so as to prevent flickering of old bulbs and electrical hazards due to worn out cables.
• Avoid direct eye contact with the light sources. This is usually achieved by positioning them property. The use of diffusers is also quite effective.

Climatic Conditions

Control of the climatic conditions at the workplace is paramount importance to the workers health and comfort and to the maintenance of higher productivity. With excess heat or cold, workers may feel very uncomfortable, and their efficiency drops. In addition, this can lead to accidents.

This human body functions in such a way as to keep the central nervous system and the internal organs at a constant temperature. It maintains the necessary thermal balance by continuous heat exchange with the environment. It is essential to avoid excessive hear or cold, and wherever possible to keep the climatic conditions optimal so that the body can maintain a thermal balance.

Working in a Hot Environment

Hot working environments are found almost everywhere. Work premise in tropical countries may, on account of general climatic conditions, be naturally hot. When source of heat such as furnaces, kilns or hot processes are present, or when the physical workload is heavy, the human body may also have to deal with excess heat. It should be noted that in such hot working environments sweating is almost the only way in which the body can lose heat. As the sweat evaporates, the body cools. There is a relationship between the amount and speed of evaporation and a feeling of comfort. The more intense the evaporation, the quicker the body will cool and feel refreshed. Evaporation increases with adequate ventilation.

Working in a Cold Environment

Working in cold environments was once restricted to non-tropical or highly elevated regions. Now as a result of modern refrigeration, various groups of workers, even in tropical countries, are exposed to a cold environment.

Exposure to cold for short periods of time can produce serious effects, especially when workers are exposed to temperatures below 10°C The loss of body heat is uncomfortable and quickly affects work efficiency. Workers in cold climates and refrigerated premises should be well protected against the cold by wearing suitable clothes, including footwear, gloves and, most importantly, a hat. Normally, dressing in layers traps dead air and serves as an insulation layer, thus keeping the worker warmer.

Control of the Thermal Environment

There are many ways of controlling the thermal environment. It is relatively easy to assess the effects of thermal conditions, especially when excessive heat or cold is an obvious problem. To solve the problem, however, consistent efforts using a variety of available measures are usually necessary. This is because the problem is linked with the general climate, which greatly affects the workplace climate, production technology, which is often the source of heat or cold and varying conditions of the work premises as well as work methods and schedules. Personal factors such as clothing, nutrition, personal habits, and age and individual differences in response to the given thermal conditions also need to be taken into account in the attempt to attain the thermal comfort of workers.

In controlling the thermal environment, one or more of the following principles may be applied:

• Regulating workroom temperature by preventing outside heat or cold from entering (improved design of the roof, insulation material or installing an air-conditioned workroom. Air-conditioning is costly, especially in factories. But it is sometimes a worthwhile investment if an appropriate type is chosen);
• Provision of ventilation in hot workplaces by increasing natural ventilating through openings or installing ventilation devices;
• Separation of heat sources from the working area, insulation of hot surfaces and pipes, or placement of barriers between the heat sources and the workers;
• Control of humidity with a view to keeping it at low levels, for example by preventing the escape of steam from pipes and equipment;
• Provision of adequate personal protective clothing and equipment for workers exposed to excessive radiant heat or excessive cold (heat-protective clothing with high insulation value may not be recommended for jobs with long exposure to moderate or heavy work as it prevents evaporative heat loss);
• Reduction of exposure time, for example, by mechanization, remote control or alternating work schedules;
• Insertion of rest pauses between work periods, with comfortable, if possible air-conditioned, resting facilities;
• Ensuring a supply of cold drinking-water for workers in a hot environment and of hot drinks for those exposed to a cold environment.

Ventilation

Ventilation is the dynamic parameter that complements the concept of air space. For a given number of workers, the smaller the work premises the more should be the ventilation.

Ventilation differs from air circulation. Ventilation replaces contaminated air by fresh air, whereas as the air-circulation merely moves the air without renewing it. Where the air temperature and humidity are high, merely to circulate the air is not only ineffective but also increases heat absorption. Ventilation disperses the heat generated by machines and people at work. Adequate ventilation should be looked upon as an important factor in maintaining the worker’s health and productivity.

Except for confined spaces, all working premises have some minimum ventilation. However, to ensure the necessary air flow (which should not be lower than 50 cubic meters of air per hour per worker), air usually needs to be changed between four to eight times per hour in offices or for sedentary workers, between eight and 12 times per hour in workshops and as much as 15 to 30 or more times per hour for public premises and where there are high levels of atmospheric pollution or humidity. The air speed used for workplace ventilation should be adapted to the air temperature and the energy expenditure: for sedentary work it should exceed 0.2 meter per second, but for a hot environment the optimum speed is between 0.5 and 1 meter per second. For hazardous work it may be even higher. Certain types of hot work can be made tolerable by directing a stream of cold air at the workers.

Natural ventilation, obtained by opening windows or wall or roof air vents, may produce significant air flows but can normally be used only in relatively mild climates. The effectiveness of this type of ventilation depends largely on external conditions. Where natural ventilation is inadequate, artificial ventilation should be used. A choice may be made between a blown-air system, an exhaust air system or a combination of both (‘push-pull’ ventilation). Only ‘push-pull’ ventilation systems allow for better regulation of air movement.

Work-Related Welfare Facilities

Work-related welfare facilities offered at or through the workplace can be important factors. Some facilities are very basic, but often ignored, such as drinking-water and toilets. Others may seem less necessary, but usually have an importance to workers far greater than their cost to the enterprise.

• Drinking Water

Safe, cool drinking water is essential for all types of work, especially in a hot environment. Without it fatigue increases rapidly and productivity falls. Adequate drinking water should be provided and maintained at convenient points, and clearly marked as “Safe drinking water”. Where possible it should be kept in suitable vessels, renewed at least daily and all practical steps taken to preserve the water and the vessels from contamination.

• Sanitary Facilities

Hygienic sanitary facilities should exist in all workplaces. They are particularly important where chemicals or other dangerous substances are used. Sufficient toilet facilities, with separate facilities for men and women workers, should be installed and conveniently located. Changing- rooms and cloakrooms should be provided. Washing facilities, such as washbasins with soap and towels, or showers, should be placed either within changing-rooms or close by.

• First Aid and Medical Facilities

Facilities for rendering first-aid and medical care at the workplace in case of accidents or unforeseen sickness are directly related to the health and safety of the workers. First-aid boxes should be clearly marked and conveniently located. They should contain only first-aid requisites of a prescribed standard and should be in the charge of qualified person. Apart from first-aid boxes, it is also desirable to have a stretcher and suitable means to transport injured persons to a centre where medical care can be provided.

• Rest Facilities

Rest facilities can include seat, rest-rooms, waiting rooms and shelters. They help workers to recover from fatigue and to get away from a noisy, polluted or isolated workstation. A sufficient number of suitable chairs or benches with backrests should be provided and maintained, including seats for occasional rest of workers who are obliged to work standing up. Rest-rooms enable workers to recover during meal and rest breaks.

• Feeding Facilities

It is now well recognized that the health and work capacity of workers to have light refreshments are needed. A full meal at the workplace in necessary when the workers live some distance away and when the hours of work are so organized that the meal breaks are short. A snack bar, buffet or mobile trolleys can provide tea, coffee and soft drinks, as well as light refreshments. Canteens or a restaurant can allow workers to purchase a cheap, well-cooked and nutritious meal for a reasonable price and eat in a clean, comfortable place, away from the workstation.

• Child Care Facilities

Many employers find that working mothers are especially loyal and effective workers, but they often face the special problems of carrying for children. It is for this reason that child-care facilities, including crèches and day-care centers, should be provided. These should be in secure, airy, clean and well lit premises. Children should be looked after property by qualified staff and offered food, drink education and play at very low cost.

• Recreational Facilities

Recreational facilities offer workers the opportunity to spend their leisure time in activities likely to increase physical and mental well-being. They may also help to improve social relations within the enterprise. Such facilities can include halls for recreation and for indoor and outdoor sports, reading-rooms and libraries, clubs for hobbies, picnics and cinemas. Special educational and vocational training courses can also be organized.