31 Mar 97
evaluate various containment and disposal methods appropriate for
DESIGN GUIDANCE SUMMARY
Designs of containment/disposal systems for AFFF discharges
should be sized for inadvertent discharges and for testing.
Open Fire Suppression Systems
a. These systems include monitor nozzles and deluge
b. Designs of AFFF containment/disposal systems should be
sized to contain the flow from largest single inadvertent
discharge for a minimum 10-minute duration. The 10-minute
duration should be increased if emergency response time to shut
down the system is anticipated to be longer.
c. Designing for a 3-minute test flow is usually not a
factor for open systems since testing usually requires less
containment than a 10-minute inadvertent discharge.
Closed Fire Suppression Systems
a. These systems include wet pipe and pre-action sprinkler
b. Design of the AFFF containment/disposal system should be
based testing of proportioning systems for a 3-minute duration.
c. To facilitate testing and maintenance, containment
systems should be sized for testing all fire suppression systems
in the same period. However, containment systems can be sized
for testing individual systems separately. Designing for the
largest single system would require the containment system to be
emptied between tests. This would extend the testing period and
increase cost for testing. Sizing the containment for a single
system should be coordinated with and accepted by the user.
Containment systems for open fire extinguishing systems can
consist of underground tanks, aboveground tanks with sump,
earthen retention ponds, containment trenches or other systems
that will achieve the containment of AFFF discharges from
inadvertent releases. For closed systems, containment should be