Chemical Engineering July 2022 - 29

Org
EPA
AIHA
NIOSH
TABLE 2. SOURCES OF EXPOSURE CONCENTRATIONS FROM VARIOUS AGENCIES
Guidance
AEGL
Target
Public
exposure
ERPG
Public
exposure
REL & IDLH Worker
exposure
OSHA
ACGIH
DOE -
SCAPA
PEL
TLV
TEEL
Worker
exposure
Worker
exposure
DOE workers
and public
Toxic fluids
The information in API 521, and thus
in this analysis, is based on the characteristics
of hydrocarbon vapors.
Thus, when effluent streams deviate
from this assumption, the system
designer is cautioned to use good
engineering judgement.
In addition to the previously idenExpect
more!
OktaLine®
Roots Pumps Meet the Requirements
of the ATEX Directive
Your added value
■ Hermetically sealed for maximum
operational reliability
■ Large pumping speed range from
280 to 8,100 m3
/h
■ All pumps can be used at ambient
temperatures ranging from -20 °C to +40 °C
■ Optimal in chemistry, biotechnology and
industrial applications such as vacuum
furnaces or heat treatment
Definition
The Acute Exposure Guideline Levels is a three-tier guideline for
emergency response for a time period between 10 minutes and
8 hours
The Emergency Response Planning Guideline is a three-tier
planning guideline for emergency response
The NIOSH recommended exposure limits (REL) calculated based
on a time-weighted average (TWA) for a 10-hour work day, short
term exposure limit (STEL) for 15 minutes and a ceiling (C) that
must not be exceeded
OSHA describes permissible exposure limits for an eight-hour
time-weighted average, a ceiling and conditions
These are threshold limit values (TLV) for an eight-hour workday
on a time weighted average (TWA), short-term exposure limit for
15 minutes (STEL), and a ceiling (C) not to be exceeded
The Temporary Emergency Exposure Limit is a three-tier guideline
developed by DOE SCAPA for use by DOE and DOE contractors
when AEGL or ERPG values were not available
tified considerations, evaluation of
toxic fluid release should consider
the followings analysis:
Vapor-phase releases. Releasing
toxic vapor to atmosphere might be
safe if the concentration of the toxic
component in the release decreases
to below acceptable threshold before
the effluent comes in contact
with personnel.
Liquid-phase releases. Releasing
toxic, volatile liquids directly to the
atmosphere should be avoided. The
discharge of liquids that are nonvolatile
(such as caustic) may be acceptable.
However, acceptance criteria
for these releases is out of the
scope of this article.
Concentration of toxics in release
streams. The diffusion and dilution
effects apply to all constituents
of the effluent. The guidance in API
STD 521 7th edition §5.8 indicates
that for typical hydrocarbon streams,
the concentration might be diluted
to below 5.0 vol.% for methane and
1.2 vol.% for hexane on a volume
basis before losing the jet momentum.
Therefore, if the toxic fluid can
be assumed to have similar characteristics
to light hydrocarbon, the
concentration of toxic components
may be diluted anywhere from 1/20
to 1/80 of the original concentration,
due to the effects of jet mixing.
Hence, Equation (6) may be used
to estimate the maximum concenPfeiffer
Vacuum GmbH
Germany
T +49 6441 802-0
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
For details visit adlinks.chemengonline.com/82583-07
JULY 2022
www.pfeiffer-vacuum.com
29
ACHEMA, Frankfurt/Main
August 22 - 26, 2022
Please visit us:
Hall 8, Booth J37
http://adlinks.chemengonline.com/82583-07 http://WWW.CHEMENGONLINE.COM
Chemical Engineering July 2022

Table of Contents for the Digital Edition of Chemical Engineering July 2022
