The Washington State SHARP Approach to Exposure Assessment - Fundamentals and Assessment Tools for Occupational Ergonomics - page 827

sampling practice for noncyclic tasks is to take a number of random samples during the task performance
period.
The job sampling approach used in the SHARP Study is based on whether the job is a single-task job or
a multiple-task job, and the tasks are cyclic or noncyclic (Figure 44.2). The first step is to determine
whether the job is a single-task job or a multiple-task job and, secondly, to determine if each task is
cyclic or noncyclic. For a cyclic single-task job, a continuous 15-min job sample is taken for the exposure
measurement purpose. For a noncyclic single-task job, three 5-min job samples are taken randomly
during the workday. This attempts to obtain good equitable exposure measures for this type of job
and capture the fluctuations of the exposure during a workday. The total job sample length for a
single task job is 15 min for both cyclic and noncyclic task jobs.
For multiple-task jobs (more than one task is performed during a workday), a different job sampling
method is used for both cyclic and noncyclic tasks. A 10-min job sample is taken for each of the cyclic
tasks and two 5-min job samples are randomly taken from each of the noncyclic tasks in a multiple-task

Single or multiple task job

Multiple task job

(limit multiple task jobs to less than

Single task job

25% of the total subjects)

Determine up to 4 major tasks
(based on duration and significance
of exposure) all exposure will be
time-weighted in the analysis.
(Jobs with more than 4 tasks will not
be selected for the study)

Cyclic or noncyclic

Cyclic task Noncyclic task

15 minutes (or at
least two cycles
whichever is longer)
video recording
during a typical task
performance period

3 five minutes video recordings during a
typical work day (recordings collected in
the morning, midday, and afternoon for
day shift, or equivalent for other types of
shift), or at least a complete task cycle if
the task is a very long cycle one.

Cyclic and noncyclic
tasks

Cyclic task

Noncyclic task

10 minutes (or at least 2
cycles whichever is longer)
video recording for each
task (max: 4 × 10 min)

2 five minutes video recording
for each task (max: 2 × 2 × 5
min) or as the single task
situation if long cycle task

1 × 15 min
recording

3 × 5 min
recording

max:
4 × 2 × 5 min
recording

max: 4 × 10
min
recording

Single task job: Total 15
minutes video recording/per
subject for analysis

Multiple task job: Maximal total
video recording of 40 minutes
per subject to be analyzed

FIGURE 44.2 Job sampling strategies depending on the type of tasks and jobs.