ASHRAE Journal - September 2023 - 16

COLUMN ENGINEER'S NOTEBOOK
for Emergency Eyewash and Shower Equipment, provides
guidance for installation, minimum performance
and use.
Separate fixtures or a combination unit can be used.
The fixture must be located so occupants can reach it
in 10 seconds or less, and the path to the fixture must
not be hindered with obstructions. An appendix to the
standard suggests 55 ft (17 m) maximum as the distance
that can be covered in 10 seconds. A door
is considered an obstruction. Therefore,
if corrosives are used, the fixture must
be in the same room as the hazard.
Flushing water must be " tepid, " which
potential safety hazard should a student leave a gas valve
open or a fire occur. For labs with two or more fuel gas
outlets, the International Fuel Gas Code (IFGC) requires
a single, dedicated shutoff valve through which all such
gas outlets shall be supplied. This allows quick shutoff
of all fuel gas to the laboratory from a single location.
The valve must be readily accessible, located in the
laboratory adjacent to the egress door and must have
FIGURE 5 The NFPA Diamond.
is defined as 60°F-100°F (16°C-38°C).
This may dictate the need for domestic
hot water service at the equipment and a
thermostatic mixing valve to ensure the
water is delivered within the required
temperature range. Most emergency
fixtures offer an option for an onboard
thermostatic mixing valve.
In general, floor drains in laboratories using hazardous
chemicals should be avoided due to the possibility
of introducing spilled chemicals into the sanitary
sewer system. This presents a dilemma regarding the
emergency eyewash and shower. Per Standard Z358.1,
an emergency shower must be capable of discharging
20 gallons/min (1.2 L/s) of water for 15 minutes.
A shower operated for 15 minutes would result in
300 gallons (1136 L) of water being dumped into the lab!
This would certainly flood the lab, surrounding spaces
and floors below. Even if a floor drain were below the
shower, it would not be able to accept this amount of
water and would likely flood the building. Cleanup
with a shop vacuum and water remediation would be
needed. One solution would be to install an underfloor
secondary containment sump with a flush floor grate
to contain the water; however, this would likely add
significant cost and may not be feasible.
Standard Z358.1 requires the emergency shower be
activated weekly. The designer may want to recommend
the owner purchase a portable test rig, which includes a
" shower sock " to direct the water to a drum or barrel.
Emergency Natural Gas Shutoff
Many school laboratories have natural gas piped to use
points on lab benches or workstations. This presents a
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ASHRAE JOURNAL ashrae.org S E PTEM B ER 2023
Flash Points
4 - Below 73°F
3 - Below 100°F
2 - Above 100°F not exceeding 200°F
1 - Above 200°F
0 - Will not burn
4 - May Detonate
3 - Shock & Heat
2 - Violent Chemical Change
1 - Unstable If Heated
0 - Stable
ACID - Acid
ALK - Alkali
COR - Corrosive
OXY - Oxidizer
# - Radioactive
--W - Use No Water
4 - Deadly
3 - Extreme Danger
2 - Hazardous
1 - Slightly Hazardous
0 - Normal Material
signage stating, " Gas Shutoff. " Several manufacturers
make products specifically for this purpose.
Conclusion
Teaching laboratories provide essential hands-on
learning for science students. However, because of
potential hazards associated with these activities,
designers must understand how to implement
engineering controls that minimize exposure risk. This
requires understanding proper ventilation procedures,
primary and secondary containment strategies and
having a solid understanding of the types of learning
activities to take place in the labs. Additionally,
designers should review all applicable codes and
standards and consult the local fire marshal to ensure
they are meeting the requirements laid out for each
specific type of system.
References
1. Kolesnikov, A, R. Ryan, D.B. Walters. 2001. " Use of
Computational Fluid Dynamics to Optimize Airflow and Energy
Conservation in Laboratory Hoods and Vented Enclosures. " EPA
Labs for the 21st Century Conference.
2. Memarzadeh, F. 1996. " Methodology for Optimization of
Laboratory Hood Containment, Volumes I and II. " National
Institutes of Health.
3. OSHA. " Code of Federal Regulations 1910.151. " Occupational
Safety and Health Administration.
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