Evolution 1.5 — Supply a FDC Sprinkler System

The first critical task of the 2nd-due engine at a standpipe building is to establish a water supply by pumping into the FDC connections.

“The second Engine Company arriving on the first alarm should take a position at the appropriate FDC standpipe connection and supply two 3″ lines into the FDC Siamese and connect to the nearest hydrant. The third arriving Engine Company should relay pump to the second engine company from the next nearest hydrant.”

This procedure continues with the next arriving engine companies if additional FDC connections to the building are available. The larger the building, the more likely multiple FDCs are present — often on different street fronts.

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-16

The manual's two engines are in series, not parallel. The 2nd due puts both 3″ lines into the Siamese — exactly what this evolution drills. The redundancy comes from the 3rd due relay-pumping into the 2nd from the next nearest hydrant: a separate arriving-company assignment, not part of a single engineer's drill. One engine, two 3″ lines into the Siamese, is the 2nd-due engineer's job — the evolution is correct as written.

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-16, verified 2026-08-30

On wet systems, pumpers augment the system so flow needs are met at adequate pressures. On dry systems, the pumpers are the only supply:

“Fire department pumpers provide the only water supply available for firefighting.”

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-16

A combined system incorporates a water supply for automatic sprinklers with a Class III standpipe system (in some cases the occupant hose connections are not required when automatic sprinklers are provided). Since the 1970s the trend has been to require automatic sprinkler systems in almost all new commercial buildings; most new systems are installed as combined sprinkler/standpipe systems.

Combined systems generally require a fire pump — electric or internal combustion (generally diesel) — to increase the pressure coming in from the public water system, in order to deliver adequate pressure at the upper levels of the building. Some codes require a backup on-premises water supply in case the public system is out of service due to an earthquake or other disruption.

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-3

Newer buildings: a single set of FDC connections supplies all fire protection systems. Older buildings may have a multitude of connections, each supplying a different area, stairwell, or system — gather this in pre-fire planning.

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-4

On a standpipe building, Engine Ops gives the FDC to the 2nd-due engine (Standpipe Operations, p.6-16). On a commercial building, the Quick Reference Guide instead assigns the 3rd Engine Company: “Position on FDC. Pump FDC upon ‘working fire’.”

The two documents agree everywhere else; this commercial-building difference is written up with page references as a question for a chief/captain.

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-16 · OFD Quick Reference Guide, May 2024, 3rd Engine Company Functions (Commercial)

FDC connections are one of the named spotting considerations for an Engine Company, and FDC Supply is listed as a tactic the Engineer must be capable of performing — alongside forward lay and reverse lay.

“Other spotting considerations for the Engine Company include water supply needs, FDC connections, line placement, fire location and intensity. Second arriving engines should position so as not to block any apparatus movement on the fireground and be able to lay a supply line from the first-in engine to the hydrant.”

The first engine should generally leave the front of the building open for the Truck's aerial.

Engine Company Operations 2023 V-1, Firefighter Assignments, p.1-9

Steps 9 and 10 are a changeover: you start on tank water, introduce the hydrant, then close tank-to-pump. The department's own changeover task spells out the order and the reason for each move.

“Air in the empty supply hose will cause problems if it enters the pump while the pump is supplying attack lines under pressure. To purge this air, open the bleeder valve on the gated intake line so that the air can escape as the supply line fills with water. When all the air has been forced from the line, close the bleeder valve. The water is now at the pump and ready for the transition.”

The printed operating procedure, in order:

• Step 1 — position safely, set the parking brake, chock the wheels.
• Step 2 — engage the pump, select the proper gear in the road transmission, lock it in.
• Step 3 — open the tank-to-pump valve (if necessary).
• Step 4 — set the transfer valve to the series position (to PSI or RPM) depending on application.
• Step 5 — increase the throttle setting to obtain the desired pressure, priming (if necessary).
• Step 6 — set the relief valve or pressure governor.
• Step 7 — open the circulator valve or partially open the tank fill valve.
• Step 8 — when an external supply becomes available, open the intake valve while closing the tank-to-pump valve (if necessary); divert enough water through the tank-fill line to replenish the tank.
• Step 9 — adjust the engine throttle to achieve the desired discharge pressure (if necessary).

Note where the relief valve sits in that order — step 6, before the external supply comes in at step 8. That is the same reason the added relief-valve step matters on 1.5.

ADO Task #19 — Basic Pump Skills, Changeover (Transition to an External Water Supply)

Pressure reducing valves regulate both residual and static pressure. Before they existed, flow-restricting devices regulated flow only, and standpipe systems using them were limited to roughly 20 stories per zone to stay inside the 175 psi maximum static pressure — each 20-story zone needing its own fire pump(s) and its own FDC.

With PRVs there is no height limit. Pressures at the lower floors of a tall building can be very high, and the PRVs are what keep static and residual pressure at an outlet inside the safe working range. The manual's own example of the scale involved:

“For example, in a 275-foot high building, a pressure of 234 psi is required at the base of the riser to overcome elevation and produce the minimum required outlet pressure of 100 psi at the riser's top outlet.”

The manual also flags what goes wrong when they are mis-set:

“Some fire departments have encountered problems where the PRV's were not properly set for the required discharge pressure. In these cases, firefighters faced either inadequate or excessive hoseline pressures.”

NFPA now requires a test/drain riser adjacent to PRV-equipped standpipe risers so flow and discharge pressure can be set and checked during regular inspections.

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-15

Before 1993: NFPA-14 required only 65 psi at 500 GPM at the highest outlet of the primary riser, with any additional risers flowing 250 GPM each. That anticipated 2½″ hose with a 1⅛″ smooth bore tip at 50 psi nozzle pressure. Maximum outlet pressure was capped at 100 psi at the required flow, maximum static at 175 psi.

The problem: departments moved to 1¾″ and 2″ attack hose with combination fog nozzles needing at least 100 psi at the nozzle.

“A 100-foot 1 ¾″ Hotel Pack (using 10 feet of 3″ as a leader line) requires 110 PSI to flow 150 GPM with a 75-PSI nozzle pressure. As you can see, this pressure will not provide an adequate fire stream for 1 ¾″ hoselines.”

1993 onward: minimum flow pressure at all outlets greater than 1½″ raised to 100 psi, maximum static still 175 psi. Pressure reducing devices required on 1½″ outlets that would exceed 100 psi flow pressure; PRVs required on all outlets exceeding 175 psi static.

“It is imperative that companies become familiar with their districts and know which high-rise buildings fall under this old standard, in order to be properly equipped with the right diameter hose line.”

Even the current minimums assume a properly maintained, 100% dependable system — the manual's words: “A scenario we must realize does not exist in many buildings.”

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-4 and p.6-14

Locations often equipped with standpipe systems:

• High-rise residential and office buildings
• Large-area buildings such as hospitals, terminals, warehouses
• Manufacturing facilities, and industrial buildings
• Enclosed shopping malls
• Theaters, stadiums, and arenas
• Above- and below-grade parking garages
• Bridges and tunnels

This evolution's drill building — a multi-story apartment — sits in the first line.

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-4

“Engine companies should never attempt to use the unlined, linen hose provided with standpipe systems. It often is old and improperly maintained and may fail under fire department operating pressures.”

The manual gives one exception: a ladder or rescue company operating remotely from an engine company while performing searches, where stretching and operating occupant-use hose would be justified in an attempt to save civilian and firefighter lives.

Engine Company Operations 2023 V-1, Standpipe Operations, p.6-3

Engine Company Operations Ch5–6 never states a pump discharge pressure for supplying an FDC — no formula, no default, no per-floor add. The 150 psi this evolution sets comes from the OFD Hydraulic Manual's own “Sprinkler Systems” entry: “150 with or without smoke showing.” Don't go looking for it in Engine Ops; it isn't there.

Engine Company Operations 2023 V-1, Ch5–6 (verified absent) · OFD Hydraulic Manual, “Sprinkler Systems” heading