Case Study

Industrial HygieneUnit IV Case Study
This assignment will allow you to demonstrate the following objectives:
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Describe sampling methods to be used for evaluating health hazards in the workplace.
Calculate the volume collected for personal sampling using the flow rate and sampling time.
Calculate the concentration of a sample given the laboratory analytical result and sample volume.
Calculate sample results from mg/m3 to ppm.
Instructions: Complete your work directly on this document. When you are finished, select “Save As,”
and save the document using this format: Student ID_UnitIV. Upload this document to BlackBoard as a
.doc, docx, or .rtf file. Show all of your work.
You are asked to evaluate employees’ exposures to methyl n-amyl ketone during a painting operation.
After careful consideration, you choose and will use NIOSH Method 2553 for the sampling.
Your pre-sampling and post-sampling pump calibrations using a primary standard are both 0.05 L/min.
You collect personal samples on two employees working in the operation. The samples are collected for
430 minutes (Sample 1) and 440 minutes (Sample 2).
1. Calculate the sample volumes for each of the samples.
The laboratory reports that the front section of Sample 1 contains 5,000 µg of methyl n-amyl ketone and
the back section contains 200 µg of methyl n-amyl ketone. The front section of Sample 2 contains 4,000
µg of methyl n-amyl ketone and the back section contains 50 µg of methyl n-amyl ketone. Neither the
front nor back sections of the field blank you supplied contain any detectable levels of methyl n-amyl
ketone.
2. Calculate the concentrations of the two personal samples in µg/L and mg/m3.
3. Convert the result to ppm (MW for methyl n-amyl ketone = 114.2). Note: Use the ideal gas
constant of 24.45.
4. Show all the steps for your calculations.
You then reference OSHA’s Table Z-1 and find that the 8-hour TWA PEL for methyl n-amyl ketone is 100
ppm.
5. Discuss how the results of the two personal samples you collected compare to the OSHA PEL,
and describe the sampling method you implemented.
You also look up the ACGIH TLV for methyl n-amyl ketone and find that the TLV is 50 ppm as an 8-hour
TWA exposure.
6. Discuss how the results for the two personal samples compare to the ACGIH TLV.
7. Discuss whether you would recommend comparing the results of your sampling to the OSHA PEL
or the ACGIH TLV. Include your rationale for the choice, and explain how you would rationalize
your choice to your employer.
Begin your assignment on the next page. The completed assignment should be a minimum of three total
pages in length (not including this instructions page). You should use at least the NIOSH document as a
reference, and you may use other resources as needed. Adhere to APA Style when creating citations and
references for this assignment. APA formatting, however, is not necessary.
UNIT IV STUDY GUIDE
Evaluating Exposures to Gases and Vapors
Course Learning Outcomes for Unit IV
Upon completion of this unit, students should be able to:
5. Explore health hazards in the workplace.
5.1 Describe sampling methods to be used for evaluating health hazards in the workplace.
6. Perform basic calculations related to industrial hygiene.
6.1 Calculate the volume collected for personal sampling using the flow rate and sampling time.
6.2 Calculate the concentration of a sample given the laboratory analytical result and sample
volume.
6.3 Calculate sample results from mg/m3 to ppm.
Course/Unit
Learning Outcomes
5.1
6.1
6.2
6.3
Learning Activity
Unit Lesson
Article: “Purpose, Scope and Use of the NIOSH Manual of Analytical
Methods”
Article: “Validation Guidelines for Air Sampling Methods Utilizing
Chromatographic Analysis”
Unit IV Case Study
Unit Lesson
Article: “Development and Evaluation of Methods”
Article: “General Considerations for Sampling Airborne Contaminants”
Unit IV Case Study
Unit Lesson
Article: “General Considerations for Sampling Airborne Contaminants”
Unit IV Case Study
Unit Lesson
Article: “General Considerations for Sampling Airborne Contaminants”
Unit IV Case Study
Required Unit Resources
In order to access the following resources, click the links below.
Read pages 1–7 of the document below.
Ashley, K., & O’Connor, P. F. (2016). Purpose, scope and use of the NIOSH manual of analytical methods. In
K. Ashley & P. F. O’Connor (Eds.), NIOSH manual of analytical methods (5th ed., pp. PS-1–PS-9).
Centers for Disease Control and Prevention. http://www.cdc.gov/niosh/docs/2014151/pdfs/chapters/chapter-ps.pdf
Read pages 1–16 of the document below.
Kennedy, E. R., Fischbach, T. J., Song, R., Eller, P. M., Shulman, S. A., & Hull, R. D. (2016). Development
and evalution of methods. In K. Ashley & P. F. O’Connor (Eds.), NIOSH manual of analytical methods
(5th ed., pp. ME-1–ME-19). Centers for Disease Control and Prevention.
http://www.cdc.gov/niosh/docs/2014-151/pdfs/chapters/chapter-me.pdf
McCammon, C. S., & Woebkenberg, M. L. (2016). General considerations for sampling airborne
contaminants. In K. Ashely & P. F. O’Connor (Eds.), NIOSH manual of analytical methods (5th ed.,
OSH 4303, Industrial Hygiene
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pp. SA-1–SA-23). Centers for Disease Control and Prevention. https://www.cdc.gov/niosh/docs/2014UNIT x STUDY GUIDE
151/pdfs/chapters/chapter-sa.pdf
Title
Read pages 5–22 of the document below.
Eide, M., Simmons, M., & Hendricks, W. (2010). Validation guidelines for air sampling methods utilizing
chromatographic analysis. https://www.osha.gov/sites/default/files/methods/chromguide.pdf
Unit Lesson
Another important task performed by the industrial hygienist is evaluating exposures to health hazards. The
image most associated with an industrial hygienist is one of sampling personal hazard exposures in a work
location. This image is simplistic and does not represent the work required to complete an accurate evaluation
of employee exposures. The process is much more complicated than most people realize.
One important decision is determining which sampling and analytical method(s) to use. Sampling and
analytical methods are highly dependent on the type of health hazard. Methods for evaluating gases and
vapors differ greatly from methods for particulates, noise, and radiation. It is common to use sorbent tubes or
badges for gases and vapors, but not for particulates. An industrial hygienist must understand the differences
in chemical states in order to accurately evaluate exposures. In this unit, we will look at the subject of
evaluating exposures to gases and vapors.
One of the first questions is whether the samples will be personal samples or area samples. Personal
samples are collected by placing a sampling device on the individual worker for a specified period of time. An
area sample is placed in an area of the workplace and not directly on a worker. Personal sampling is the
preferred method for evaluating employee exposures and determining OSHA compliance. However, in some
cases, placing a sampling train on an individual can create an additional hazard that may result in an
unacceptable risk to the employee. If this is the case, area samples will be used. In some regulations, OSHA
specifies that the exposure monitoring will be made from breathing zone air samples (OSHA, 1970b). In other
regulations, OSHA does not specifically state that the samples must be collected in the breathing zone, but
that they must be representative of each employee’s exposure (OSHA, 1970c).
Another important consideration is the time period of the sampling. One variable that affects the sampling
length is the type of occupational exposure limit (OEL) that exists for the health hazard. OSHA publishes
legally enforceable OELs called permissible exposure limits (PELs). NIOSH publishes recommended
exposure limits (RELs), and the American Conference of Governmental Industrial Hygienists (ACGIH)
publishes threshold limit values (TLVs). These are often more stringent than the established OSHA PELs but
are not legally enforceable by OSHA. All three of the entities use three types of OELs: time-weighted average
(TWA) OELs, short-term exposure limits (STELs), and ceiling concentrations (C). Some health hazards will
only have a TWA OEL, some only a STEL, some only a C, and some will have a combination of all three
OELs. Each of the three types of OELs may require a different sampling length.
TWA OELs represent an exposure for an 8-hour work shift during a 40-hour workweek. Sampling for health
hazards with a TWA OEL requires a full-shift sample. It is often not feasible to sample for the whole work shift
because employees have time at the start and close of the work shift where they get ready for work and get
ready to go home. Additionally, when a number of samples are necessary, it takes time to place sampling
devices on all the workers. Therefore, full-shift samples will typically be for a time period between seven and
eight hours. OSHA specifies that a full-shift sample must be collected for at least seven continuous hours
(OSHA, 1970d). OSHA may also publish a substance-specific standard that contains an action level. The
action level also represents a TWA exposure that, if exceeded, requires the employer to take specific actions
(OSHA, 1970e).
Short-term exposure limits (STELs) should not be exceeded for a shorter time period, typically 15 minutes, as
long as the 8-hour TWA OEL is also not exceeded for the work shift. OSHA does not use STELs in Tables Z1, Z-2, or Z-3. OSHA has established some STELs in substance-specific standards (OSHA, 1970g). Some of
the terminology OSHA uses for short-term limits may be confusing. For example, in some substance-specific
standards, OSHA uses the term excursion limit, which is defined the same way as a STEL (OSHA, 1970f).
The ACGIH assigns STELs for many more health hazards than OSHA. According to the definition of STEL,
OSH 4303, Industrial Hygiene
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samples collected to evaluate short-term exposures are collected for only 15 minutes
(or another
time limit set
UNIT x STUDY
GUIDE
by OSHA).
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The third type of OEL, the ceiling concentration, represents an exposure not to be exceeded at any time
during the work shift. OSHA does include ceiling limits for some health hazards in Tables Z-1 and Z-2 and in
some substance-specific standards. Evaluating exposures with an established ceiling concentration can be
difficult. Most laboratory analytical methods are not designed to detect chemicals instantaneously. For some
compounds, instantaneous monitoring can be performed using a direct-reading meter; however, sensors have
not been developed for many of the chemicals with an established ceiling concentration. Therefore, OSHA
specifies that a 15-minute sample can be used to evaluate the exposure (OSHA, 1970a).
The choice of a sampling and analytical method will determine the sensitivity and accuracy of the sampling to
be performed. If the industrial hygienist chooses an incorrect method, the laboratory may not be able to detect
the compound in a 15-minute sample at the level that has been set as a STEL or ceiling concentration.
Receiving a lab result of