Safety Sampling

It is a systematic sampling of particular dangerous activities, process of area. It’s a method a method of measuring hazard or accident potential by random sampling and by counting safety defects while touring specified location by a prescribed tour of 15 minutes at the weekly intervals. The quantum of defects noticed is used to portray trends in safety situation. The point on safety sampling sheet includes items such as non-use of personal protection, obstructed fire exit, environmental factors, lighting, ventilation, temperature, faulty hand tools, guarding position, Housekeeping machinery condition etc. The results are collected by the safety officer and presented in graph form to monitor the effectiveness of the safety programme.

safety sampling formula

Gives number of observation N,

When percentage of unsafe operations P and value of accuracy V (normal value = 10%) are know. For example if during preliminary survey of 60 observations, 20 were found unsafe then

safety sampling formula for site inspection

This means 812 sample observations would be required to ascertain various unsafe practices with an accuracy of 10%. If 200 observations are possible in one tour, four tours (three tours of 200 and last tour of 212 0bservation) will be required for satisfactory result.




This technique was first employed by American chemical plants and then by ICC’s Dyestuffs Division in UK. It is based on Heinrich’s ratio 1:29:300 opportunities must be observed before one lost time accident. It is based on samples and not on detailed surveys.

Its difference with safety tour is that the tour is an unscheduled examination of work area by a team of safety personnel and may last for a longer period to assess safety standards, while safety sampling is a short tour of 15 minutes generally by one observer for the purpose of random sampling of visible defects and to mark them on a safety sampling checklist.

Steps of the technique are:-

  1. List safety defect and hazards applicable to the area.
  2. Define routes at least two per section or department which the observer can traverse within 15 minutes.
  3. Train the observers for correct use of their respective routes and printed checklists.
  4. Tell the workers the purpose of safety sampling.
  5. Observers must meet at a convenient place once a week or fortnight. One observer should cover one route alone and mark his sheet.
  6. Defects found should be corrected by supervision or department Head.
  7. Result of sampling Check List are added to summary sheets and plotted on a graph.

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