32
Agent Distribution Piping
The agent distribution piping shall be 3/8” NPT Schedule 40 black iron, 3/8” NPT Schedule 40 stainless
steel, or 1/2” Pro-Press copper fittings. Fittings shall be minimum class 150. Nozzle drops cannot be
sleeved in steel but can be made from polished stainless steel, or polished chrome-plated black iron.
Galvanized pipe or fittings must not be used. Pipe thread or compound should be used to help seal fittings.
Distribution piping can be run in single cylinder or dual cylinder manifold configurations. Refer to page 34
for single cylinder and dual cylinder configuration details.
The distribution network consists of a supply line and all applicable branches depending on the protected
hazards. Branch lines include the plenum branch, duct branch, overlapping nozzle appliance branch, and
dedicated nozzle appliance branch.
The supply line is defined as the run of all pipe and fittings from the tank outlet to the last branch line,
including fittings at the start of all branch lines. All branch lines start at the outlet of the applicable supply
line fitting and do not include the supply tee.
A plenum branch is defined as the run of all pipe and fittings from the supply line tee outlet to the plenum
nozzle(s).
A duct branch is defined as the run of all pipe and fittings from the supply line tee outlet to the duct noz-
zle(s). Duct branch lines on risers greater than 75 inch perimeter can have a “tee” installed. Two separate
duct branch lines are not required.
An overlapping nozzle appliance branch is defined as the run of all pipe and fittings from the supply line tee
outlet to the nozzle.
A dedicated nozzle appliance branch is defined as the run of all pipe and fittings from the supply line tee
outlet to the nozzle.
Refer to page 33 and page 34 for Supply Line, Plenum Branch, Duct Branch, Overlapping Nozzle
Appliance, and Dedicated Nozzle Appliance information.
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