Evolution 1.9 — Pump to a ladder company for an elevated stream

Most structure fires an Engine Company meets are handled with handlines. Occasionally a fire cannot be controlled with them and the engine has to deliver large quantities of water from a great distance.

By most definitions, any stream greater than 350 gpm that requires mechanical assistance for handling is a master stream. Also called large-caliber streams (LCS), these long-reaching, high-volume streams may be portable (ground-based), elevated — including ladder pipes and nozzles attached to elevating platforms — or mounted atop the engine apparatus itself. This evolution is the elevated case, supplied by the engine.

Engine Company Operations 2023 V-1, p.7-1. The printed text hyphenates “mechan-ical” across a line break; corrected here.

Chapter 7 spends most of its length on the engine's own master streams. They are different appliances with different losses, and grabbing the wrong figure is the easiest way to mis-pump this evolution.

The manual's descriptions of the engine's own devices, for the contrast: the Stinger is a dual-purpose break-apart monitor plumbed to an outlet on top of the engine, so it goes into operation without running a supply line to it. Its drawback is that the deck-gun configuration may require the engine to be parked close enough to get reach — which puts the apparatus in a potentially dangerous position. Removed from the engine it mounts to a portable base with a single 5″ LDH inlet and folding legs, which is how you get the device away from the apparatus. The R.A.M. is a light, compact portable monitor a single firefighter can deploy, supplied by 2½″ or 3″ hose, with a maximum delivery of 500 gpm at 75 psi nozzle pressure and a waterway designed for minimal appliance loss.

None of that is what you are pumping here. On evolution 1.9 the device belongs to the truck and sits at the tip of a raised aerial — which is why the appliance term, and the elevation term with it, come from the aerial entry and nowhere else.

Engine Company Operations 2023 V-1, pp.7-4, 7-5 and 7-6 · OFD Hydraulic Manual, Appliance Loss — large appliances. Chapter 7's Stinger paragraph prints “A disadvantaged of using the Stinger”; wording corrected, sense unchanged.

Master stream operations require a coordinated effort from the companies operating on scene, “one of which is ensuring that all department members have been backed out of the building prior to flowing any master stream or elevated ladder pipe.” The manual names the elevated case explicitly. That is the gate in the master-stream section above.

Putting master streams into service generally means interior offensive operations have been abandoned and a defensive posture is being employed — but “generally” is not “always”, which is exactly why the confirmation is a two-way acknowledgement.

Engine Company Operations 2023 V-1, p.7-1

The device must be positioned to provide an effective stream, because once the line is in operation it must be shut down to be repositioned. The safest exterior positions are at the corners of the building. Setting up in front — from the top of the engine or from the ground — is “a dangerous and ineffective tactic”; firefighters operating the stream are then in the collapse zone and may not have time to react to a sudden collapse of an exterior wall.

If a front position is unavoidable it must be set back far enough not to be struck by falling walls or debris. The collapse zone is one and one-half times the height of the tallest exterior wall — a 20-foot wall gets 30 feet, the further the better.

This governs where you park too: your engine is tied to the truck by LDH, and setup step 3 pushes you to keep that lay short. Short and out of the collapse zone, not short instead of it.

Engine Company Operations 2023 V-1, pp.7-1–7-2. Two printed slips on 7-2 are corrected here without changing the sense: the front-of-building sentence is missing its verb and reads “so that is will not be struck”, and the deck-gun paragraph below it reads “imposed by a narrow streets”.

The first safety consideration the manual raises is not the appliance, it is the building: higher flows are more likely to knock debris loose and send it through the air into people or apparatus. An elevated stream is the highest-flow, highest-angle version of that.

The second consideration is portable-mode specific — a portable monitor has a limited side-to-side range and can be tipped over by turning the nozzle too far left or right. It is listed here because the same chapter covers both, not because it applies to an aerial.

Engine Company Operations 2023 V-1, p.7-1

The Engineer of the first arriving engine has to give the Company Officer a sufficient view of the fire building, and generally leave the front of the building open for the Truck's aerial if needed. Other spotting considerations are water supply needs, FDC connections, line placement, and fire location and intensity.

Positioning the first engine as close as possible to the fire building “requires a coordinated effort between the Engineer, the Engine Company Officer, and the first arriving Truck Company for optimal placement.” Second arriving engines position so as not to block apparatus movement on the fireground.

And when stretching from the apparatus: “The apparatus should be positioned so that it will not interfere with Truck Company operations.” A hydrant near the fire building may be used only if it allows a rapid stretch and will not interfere with ladder company positioning.

Engine Company Operations 2023 V-1, Ch.1 Firefighter Assignments, pp.1-9, 1-10 and 1-11

Setup step 1 sends you to the ladder company for placement. The Truck Manual tells you what they are thinking about. It breaks aerial positioning into four considerations — uninvolved to involved, corners, inside vs. outside, and pull past / stop short — and two of them decide how far you will be pumping.

• Uninvolved to involved. The truck spots to create distance between where the fire is and where it is going, which also sets them up “to protect uninvolved portions of the building if anticipating using aerial master streams.”
• Inside vs. outside. An inside spot needs a longer throw. An outside spot allows Engine companies to position closer to the building underneath the Truck's ladder — it gets the waterway out of the way, gives a better climbing angle, and “sets us up for aerial master stream operations should the need arise.”

That is setup step 3 from the other side of the radio. The truck taking an outside spot is what makes a short LDH lay possible; if they have to go inside, expect the lay — and the F term — to grow.

The manual's own caution on the “the Truck takes the numbers” habit applies here too: hose can be extended and ladders cannot, but a poorly positioned truck can delay an arriving engine from laying to the fire.

2026 OFD Truck Manual v3.1, Section 6 Apparatus Positioning, p.143

The reverse-lay section defines the two ways LDH is used:

• Supply evolution — LDH connected between the suction side of the pump and the hydrant.
• Attack evolution — LDH connected between the discharge side of the pump and “an appliance or master stream.”

Out-of-cab 6 is the supply evolution; out-of-cab 8 is the attack evolution. On a reverse lay the engine sits at the water source and supplements hydrant pressure to the rig in front — which is one way this evolution gets set up when the truck arrives first.

On the forward-lay side the department's rule is “5″ LDH first”: the connection shall be made using 5″ LDH, and only if that cannot be secured on the hydrant are a minimum of two 3″ hoses connected, one on each side.

Engine Company Operations 2023 V-1, p.5-9 and Ch.1 Firefighter Assignments, p.1-11

An elevated master stream is a high-flow load, so the supply question is a real one before you ever set a PDP.

• Provide one 5-inch hose line for every 1,000 gpm to be delivered. p.5-5
• A double 2½″ hydrant — two 2½″ outlets fed by a 4″ main, no steamer — should be expected to give less than 600 gpm. That will not carry a large tip. p.5-4
• A single 5″ line may not flow all of the water available from a hydrant or water main. p.5-5

When one hydrant is not enough, the manual ranks the tactics from least to best preferred. It introduces them as “three basic tactics” and then prints four — all four are reproduced here:

1. Multiple supply lines from a single hydrant.
2. Pumping the hydrant with the 2nd or 3rd due engine supplying the attack pumper.
3. Multiple supply lines from different hydrants sharing the same water main.
4. Multiple supply lines from different hydrants not sharing the same water main.

If the water is remote, relay pumping applies: a water supply pumper at the source (the largest pumping capacity available), relay pumpers boosting pressure down the line, and the fire attack pumper at the scene supplying the lines and appliances. Orem uses the Constant Pressure Relay method.

Engine Company Operations 2023 V-1, pp.5-4 and 5-5, p.5-13, pp.5-14 and 5-15. The remaining flow bullets printed on 5-5 conflict with 5-4 and are on the error list — not published here.

Orem uses the Constant Pressure Relay method. An elevated stream is exactly the load that forces the question, because the flow you need may be more than one hydrant near the fire can give.

1. Position the attack pumper.
2. Position the source pumper at the “key” hydrant.
3. Lay out hose and place relay pumpers at 750-foot intervals.
4. All pumpers except the source pumper open a discharge to exhaust air from the lines.
5. Source pumper throttles up to 175 psi.
6. The 1st relay pumper closes its unused discharge once a steady stream flows through it, then throttles up to 175 psi — and every successive relay pumper follows the same procedure.
7. All driver/operators set their intake relief valves.
8. The attack pumper adjusts PDP to supply the attack lines, maintaining water flow during temporary shutdowns by using one or more discharges as waste or dump lines.

Source and relay pumpers hold 175 psi PDP; the attack pumper adjusts as needed and dumps excess pressure. That 175 accounts for 20 psi residual pressure for the next pumper in the relay.

The ceiling on the whole operation is the hose layout. Maximum volume at 750 feet:

Read that against the tip you are feeding. A single 5″ relay leg tops out at 1,607 gpm, so a 2″ tip at 1,000 gpm fits; a single 3″ leg at 508 gpm does not even carry a 1½″ tip. One mile is 5,280 feet, which is seven 750-foot intervals.

OFD Hydraulic Manual, Constant Pressure Relay (Limited Max Volume) — implementing steps, maximum volume table and key positions · Engine Company Operations 2023 V-1, p.5-15

Transitioning from tank water to a pressurised external source is its own task with its own nine steps. The ones that bite on this evolution:

• Step 1 — position safely and immobilize: parking brake and chock the wheels.
• Step 6 — set the relief valve or pressure governor. Sixth of nine, before pressure is put to the line, not last.
• Step 8 — when the external supply becomes available, open the intake while closing the tank-to-pump, and divert enough water through the tank-fill line to replenish the tank.

Air in the empty supply hose causes problems if it enters the pump while the pump is supplying lines under pressure — open the bleeder on the gated intake so air escapes as the line fills, and close it once the air is out. Then open the intake very slowly while watching the intake and discharge gauges. A full tank is a limited reserve if the external supply is lost unexpectedly.

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

The Engineer “must know how many hose lines, size, length, nozzles, and the flow rates of their apparatus (per OFD hydraulic standard)” — which is why the sheet's note about different nozzles and tip sizes on the truck's elevated master stream is a calculation instruction, not a footnote.

In order to establish and maintain proper pumping pressures, all Engineers must know how many hoselines, the size and length of the hoseline, the type of nozzles being used, and their flow. They must listen closely to the radio at all times for traffic concerning charging, shutting down or adjusting hose line pressures, and monitor the residual pressure of the pump master intake gauge to determine the capability of supplying additional volumes.

The Engineer's suppression duties are listed as water supply, pump operations, and observing the condition of all hoselines stretched — and the Engineer must recognise the need for and initiate supply line operations when required.

Engine Company Operations 2023 V-1, Ch.1 Firefighter Assignments, pp.1-8, 1-9 and 1-11

On residential, mid-rise and commercial alike the 1st Truck Company positions to cover side Alpha. The 2nd Truck Company covers side Charlie — “when possible” on residential, stated without that qualifier on mid-rise and commercial. On a mid-rise, ladder drivers remain with the rig to set the aerial device and work with other ladder drivers or crew on exterior operations, ventilation and utility control.

On the engine side the 2nd Engine Company completes water supply and pumps the hydrant for the 1st engine if needed; on commercial the 4th engine initiates a 2nd water supply on a “working fire”. If you are the one pumping the truck, know which engine owes you the hydrant.

OFD Quick Reference Guide for Initial Company Operations, May 2024. The guide states it is a quick reference and does not replace the full manuals.