Chapter 4

Maintenance Work Measurement

Chapter Objectives

1. Enable students to understand the role standard time plays in

improving maintenance systems

2. Enable students to understand the basic techniques for developing Standard times for maintenance work

Chapter 4 Objectives

3. Enable students to evaluate the adequacy of the existing time standards maintenance

programs.

5. Enable students to use time standards effectively in maintenance

Role of Standard Times (ST)

1.  Aid in evaluating the performance of workers

2. Enable effective planning and control of maintenance resources.

3. Aid in scheduling

4. Enable management to gauge productivity.

Time Standard

It is the required time by a qualified worker working at standard pace to perform a job.

Qualified worker is one who has acquired

the necessary skills, knowledge and other attributes necessary to carry out the

work to satisfactory standard of quantity, quality and safety.

Time standards

Standard pace ( performance ) it is the rate that a qualified worker naturally will achieve as an

average over the working day.

Nature of Maintenance Work

Occurs randomly

High variation

Various places

Varying environmental conditions

Work Measurement

Techniques

Measurement Measurement

Direct Indirect

Time

Study

Work

Sampling

Pre-determined

Motion Time

Systems

Estimating

Standard Data

Comparative

Estimating

J ob Standards

Time study

Time study is performed by timing the worker as the job is performed, summing the times for the pertaining elements of the job, standardizing the observed times and adding allowances for personal and other working conditions.

Steps of Time Study1. Select the job ( Standardize the job in terms of material and the operator )

2. Break the jobs into elements

3. Observe the job

4. Compute the basic time

( BT = OT * ( Rating/ Standard rating)

BT = Basic time, OT = Observed time

Standard rating = 100%

Steps of Time Study

5. Determine allowances

6. Establish job standards

Job Standards = BT( 1 + ALL) ALL = AllowancesTable 4.3 provides guidelines for allowances.

Work Sampling

Work sampling is a technique for finding the percentage occurrence of a certain activity using statistical sampling. It can be applied to see the

utilization of a maintenance worker, machine utilization, etc.

Example

A worker is observed randomly 1000 times. In 750 times he was busy. In 250 he was idle.

Utilization = 750/1000 = 0.75 Confidence interval for utilization is

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n 2

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pq

n 2

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n 2

Planning work Sampling study

1. Define clearly the objective of the study

2. Determine the population of the study.

3. Activity definition4. Observation form design5. Observation route planning

Planning work Sampling study6. Fix study schedule

7. Determine number of observations

8. Observation time schedule

9. Sample population preparation

10. Observer training

Predetermined Motion – Time Systems

Pre-determined motion time systems are used for setting job standards. One of the better known pre-determined motion times systems is the Method-Time Measurement (MTM). The fundamental motion times are the result of studying a large sample of diversified operations 

Predetermined Motion – Time Systems

For setting a job standard, an analyst would break the job into the basic motions required to perform it and then sum the appropriate pre-determined times for all the basic motions involved.

Procedure for Setting a Predetermined Standard

1. Observe the job or think it through if it is yet to be establish

2. Break the job into elements and record each element.

3. Obtain time units for each job element from the tables.

4. Add the total motion units for all elements.

  

Procedure for Setting a Predetermined Standard5. Estimate allowance for personal time,

delays and fatigue. 6. Add the performance motion time and

allowance units for a standard job motion unit together and compute the motion units to actual time in minute, hour etc. PMTS can be used for developing job standards even before the work get started.

Standard Data

Standard data refers to standard data banks for various elements which occur repeatedly in the workplace. These elements can be put together to develop job standards.

Developing standard Data

Several maintenance jobs in a company may contain the same work elements. It is not necessary to time these work elements in every job if a reasonable job standard has been determined from one or more previously studied jobs. In the maintenance department a data base can be maintained for work element duration obtained through previous time studies or by pre-determined motion time systems

Estimation

Estimating is the process of using past experience to predict future events. It can be used to develop job standards in an expensive way.

 

Advantage and Disadvantage of this method

Comparative Estimating ( Slotting)

The basis of comparative estimation is its reliance on a series of benchmark jobs. These benchmark are jobs, representative of a range of jobs, which are similar in work requirement, types of tools used etc. and are capable of being measured by accepted time measurement techniques