Engine Operations›Water Supply
The Officer picks the tactic. The Engineer recognises the need, initiates it, and keeps it flowing.
RECOGNISE THE NEED AND INITIATE THE SUPPLY LINE.
Arriving other than first due does not release you — you stay aware of the water supply needs of the units already on scene.
"The Engineer must recognize the need for and initiate supply line operations when required. When arriving other than first due, the Engineer must remain aware of water supply needs of units already on the scene."
The three suppression duties listed for the Engineer are water supply, pump operations, and observing the condition of every hoseline stretched. The tactics the Engineer must be capable of performing are Forward Lay, Reverse Lay and FDC Supply.
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, p.1-9
FOUR OPTIONS. THE OFFICER PICKS ONE — AND SAYS IT ON THE RADIO.
Lay-in wet · lay-in dry · reverse lay · hand-jack.
Muscle memory
If you did not hear the water supply call, ask for it before you leave the seat. The second due cannot adjust to a plan that was never transmitted.
"Locating a water source. The officer has several options for securing a water supply; lay-in wet, lay-in dry, reverse lay, or hand-jack. If unable to take supply MUST notify the next incoming company to lay in a water supply."
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, p.1-3
Chapter 5 puts the same duty in stronger terms:
"Whatever decision the first-in Company Officer chooses to select, they MUST announce over the radio their water supply intentions so that the second due engine can adjust their strategies accordantly."
The first arriving engine may elect to pass up a water supply, attack off tank water and assign the supply line to the second due engine; or lay in dry; or lay in wet. Direction of lay and wet-or-dry are two separate choices.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-1
SPOT FOR A FORWARD LAY BY DEFAULT.
A hydrant in the immediate vicinity of the fire building can be used — if it allows a rapid stretch and does not interfere with ladder company positioning.
"The Engineer should position the apparatus for a Forward Lay whenever the need for water supply is determined. A hydrant in the immediate vicinity of the fire building may be used if it allows for a rapid stretch and will not interfere with ladder company positioning."
Other spotting considerations named for the engine company: water supply needs, FDC connections, line placement, fire location and intensity.
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, pp.1-9–1-10
SECOND DUE SUPPLIES THE FIRST — FROM THE HYDRANT, NOT FROM THE FRONT.
Lay away from the first engine, spot on the hydrant, connect, supply. Second engines position so they block nothing on the fireground.
"The Engineer of the second arriving engine is assigned to supply the first engine, this should be accomplished without placing their apparatus at the front of the fire scene. This is best accomplished by laying a supply line away from the first engine, spotting the second engine at the hydrant, connecting to that hydrant, and supplying the first arriving engine."
The determination of the need for water supply is made by the first arriving Engine Company Officer, who either takes it or hands the responsibility to the second arriving engine — and in either case transmits that information from first to second.
Second arriving engines are also told to position so as not to block apparatus movement on the fireground and to be able to lay a supply line from the first-in engine to the hydrant. Third and later engines stay out of the direct fire scene, or take the alley behind the structure to get additional lines in more easily.
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, pp.1-9–1-11
5″ LDH FIRST.
If the 5″ connection cannot be secured on the hydrant, go to a minimum of two 3″ hoses — one on each side of the hydrant.
"When performing a Forward Lay, the connection shall be made using 5” LDH, in the event the 5” LDH connection cannot be secured on the hydrant a minimum of 2-3” hoses shall be connected, one on each side of the hydrant. Pony lines are acceptable where connections are short as long as ‘5” LDH first’ rules are applied."
And a positioning reminder attached to the same paragraph: when stretching hose lines from the apparatus, the apparatus should be positioned so it will not interfere with Truck Company operations.
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, p.1-11
WATCH THE MASTER INTAKE GAUGE.
Residual pressure on that gauge is how you know whether there is more volume in the hydrant to give.
Muscle memory
Read the intake before you flow, then again after each line is charged. The difference between those two numbers is the whole answer — see 1st digit.
"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. It is imperative that the Engineer listen closely to the radio at all times for traffic concerning charging, shutting down or adjusting hose line pressures on hose lines. They should also monitor the residual pressure of the pump master intake gauge to determine the capability of supplying additional volumes when available or as needed."
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, p.1-11
The same duty is listed in the Engineer's numbered responsibilities: "Must know how many hose lines, size, length, nozzles, and the flow rates of their apparatus. (per OFD hydraulic standard)"
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, p.1-8
NOTHING SHOWING: PUMP IN SERVICE, NO HYDRANT CONNECTION YET.
Complete every step to put the pump in service and supply water to hose. Stay by the pump and monitor the radio. Make the hydrant connection when fire involvement warrants it.
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, p.1-9
HAND-JACKING THE LDH IS A HOSE TASK — THE BACK-UP FIREFIGHTER OWNS IT.
Hand-jack the LDH back to the plug and complete the hydrant connection.
Under the Back-Up Firefighter's three key elements of hose work — assisting the stretch, flaking and chasing kinks, assisting the advance — stretching is broken out by line type. For LDH:
"Hand jack LDH back to the plug and complete the hydrant connection for water supply operations."
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, p.1-24
Hand-jack is also one of the four water supply options the Officer may select on the response in.
Engine Company Operations 2023 V-1, ch.1 Firefighter Assignments, p.1-3
Dry-barrel is what you should expect to find. Three parts: barrel, discharge outlets, stem.
DRY-BARREL: STEM CLOSED MEANS THE BARREL IS EMPTY.
The main valve sits below the frost line underground, which is what keeps water out of the barrel. From the top of the stem down to the main valve there is normally no water.
"As the name implies, when the stem valve is closed, the barrel from the top of the hydrant, down to the water main is empty. The main valve is located below the frost line underground, which prevents water from entering the barrel."
The three basic components associated with the hydrant: Barrel, Discharge outlets and Stem (shut off valve).
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-2
STANDARD HYDRANT: ONE 4½″ STEAMER + TWO 2½″.
In commercial or high-occupancy areas you may find hydrants with two steamers.
"The standard hydrant will have one 4 ½” (steamer) outlet and two 2 ½” outlets. In commercial or high occupancy areas, you may encounter hydrants with two steamers."
"All outlets have National Standard Threads (NST) per NFPA. The diameter of the outlets are 2 ½” or 4 ½”."
Type, size and spacing are determined by the water district the hydrant sits in, so the mix changes as you cross jurisdiction lines.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-2
OPEN LEFT.
Counter-clockwise is the nationally recognised direction to open a hydrant stem valve, and every water district and municipality surrounding Orem follows it.
"The nationally recognized direction to open hydrant stem valves is counter-clockwise(‘Open-Left’). All water districts and municipalities that surround the City of Orem follow these standards."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-5
KNOW THE THREE HYDRANTS YOU WILL ACTUALLY MEET.
Standard dry-barrel · double 2½″ · private systems.
"The most common dry–barrel hydrant found within the Orem Fire response area. Comprised with two 2 ½” outlets and one steamer outlet." Current city code allows Mueller Centurion, Waterous Pacer or Kennedy Guardian; older hydrants may be found in the city and the functions are similar.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-3
"A dry-barrel hydrant with two 2½” outlets. These outlets are feed by a 4” Main, expected flows are less than 600gpm." Hydrant locations across the city are published on the city's GIS web map.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-4
"There are a few locations throughout the city that contain privately owned hydrants systems. The maintenance and repair of these systems is the responsibility of the HOA or business owner/management. The Orem City water department may flow test these private hydrant systems if staffing and time allow."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-4
THE HYDRANT BAG GOES TO THE HYDRANT AND STAYS THERE.
Stowed in the rear compartment. Depending on arrival order and the type of lead being performed, either the 1st or the 2nd due engine leaves the bucket and its contents at the plug.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-6
Do not get caught
Once that hydrant is charged, no additional line may be added to another outlet unless you shut the hydrant down, or a shut-off valve was already fitted before charging.
So on a multi-outlet dry-barrel hydrant, a 2½″ gate valve goes on an unused outlet at the onset of the operation — before the wrench turns, not after somebody asks for more water.
Muscle memory
"It is important to remember, when a dry-barrel hydrant is charged no additional lines may be added to the other outlets unless the hydrant is shut down or a shut off valve is added prior to charging."
"When the stem valve is opened, water is supplied to ALL outlets at the same time. To accommodate additional water supply needs, multi-outlet dry barrel hydrants must have a 2 1/2” hydrant gate-valve attached to an unused outlet at the onset of any hydrant operation."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-2
The hydrant bag carries two of those gate valves for exactly this.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-6
Two figures are operative, and one of them is a warning about the hydrant in front of you.
A DOUBLE 2½″ IS A SMALL HYDRANT.
No steamer on the barrel is the tell. Treat it as a supplement, not as your supply for a working fire, and plan the second source early.
"A dry-barrel hydrant with two 2½” outlets. These outlets are feed by a 4” Main, expected flows are less than 600gpm."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-4
ONE 5″ SUPPLY LINE PER 1,000 GPM TO BE DELIVERED.
And a single 5-inch line may not flow all of the water that is actually available from the hydrant or the main — the line can be the restriction, not the water.
The chapter opens the section by naming what moves the number:
"The amount of water available to an engine company through a fire hydrant may vary based on many factors, including main size, pressure in the system, and the amount of hydrants being operated off the same main at the same time."
Some of those factors are outside the engine company's control. The two bullets this page publishes:
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-5
Other flow bullets printed on that same page are not published here — see the flagged item at the bottom of this page.
MORE HYDRANTS ON ONE MAIN = LESS WATER EACH.
Main size, system pressure, and how many hydrants are being worked off the same main at the same time. That last one is the one you can do something about — it is why the high-flow order of preference below ends with different mains.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-5
Your intake gauge tells you how many more like volumes the hydrant has in it. Two readings and one multiplication.
READ THE STATIC INTAKE BEFORE YOU FLOW.
That number is the basis of everything below. Take the first digit of it.
MULTIPLY THAT FIRST DIGIT BY 1, 2 AND 3.
Those three products are your bands. On a 90 psi intake the first digit is 9, so the bands are 9, 18 and 27.
CHARGE THE LINE, READ THE INTAKE AGAIN, TAKE THE DROP.
The drop — the R-difference — falls into one of the bands and tells you how many more lines of that same volume the hydrant will carry.
Worked on a 90 psi intake
Table scrolls sideways →
| Band | Intake drop (R-difference) | Like volumes left | What that means at the panel |
|---|---|---|---|
| 9 × 1 | 1–9 psi | 3 | Three more lines of the same volume. |
| 9 × 2 | 10–18 psi | 2 | Two more lines of the same volume. |
| 9 × 3 | 19–27 psi | 1 | One more line, and you are done. |
| — | 28 psi or more | 0 | Nothing left. Get another source. |
Example: intake reads 90 static. You charge a 150 gpm line and the intake settles at 84. Drop of 6 → the 1–9 band → 3 like volumes — three more lines of that same flow before the hydrant is spent.
9 / 18 / 27 ARE NOT THE NUMBERS. THEY CAME FROM A 90 PSI GAUGE.
Recompute the bands off whatever your intake actually reads. A 60 psi intake gives a first digit of 6, so the bands become 6, 12 and 18 — a 14 psi drop that would have left you two like volumes at 90 psi leaves you one at 60. Memorising the worked figures is how you over-promise water.
Muscle memory
First digit of the gauge in front of you × 1, 2, 3. Never the digits off a training slide.
NET PUMP DISCHARGE PRESSURE IS THE WORK YOU ARE ACTUALLY DOING.
NPDP = PDP − intake. A 150 psi PDP on a 90 psi intake is 60 psi of net work, because no work is being done on the suction side of the pump.
"NPDP = PDP – INTAKE. No work is being performed on the suction side of the pump. This is the total work of the pump. Therefore, the incoming pressure must be subtracted from the discharge pressure." Worked in the standard as: "PDP of 150 psi – Intake of 90 psi = Net of 60 psi. This is how much work the pump is actually doing."
The standard prints this worked example only, at a 90 psi intake. The method itself is the first digit of your intake reading multiplied by 1, 2 and 3.
OFD Apparatus Driver / Operator Hydraulic Calculation Standards (Target Solutions), §3 Net Pump Discharge Pressure and §4 Calculating Like Volumes — the document is unpaginated.
This is the standard chapter 5 sends you to for relay pressures and distances.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-15
Pump work lives on Pump Operations
Forward, reverse, split. Chosen on arrival order, direction of travel, occupancy type and anticipated water needs — and announced before it is executed.
Forward lay — hydrant to fire
STOP AT THE HYDRANT, LASSO THE LDH AROUND IT, DROP TOWARD THE FIRE.
Depending on the lead the Officer selects, the Back-Up firefighter can be left at the hydrant to complete the connection.
"A Forward Lay is a supply line evolution that starts with the laying of a hose-line from a hydrant / water source, and proceeds to the fire (hydrant-to-fire). The forward lay operation is used when the engine stops at a hydrant, ‘Lassoes’ the LDH around the hydrant and drops the supply line toward the fire building."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-7
"This evolution is typically done by either an engine company providing its own water supply, or by one company supplying another company already on scene."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-8
WET LEAD — SOMEBODY STAYS.
The Back-Up firefighter remains at the hydrant and charges the line when the command to do so is received.
DRY LEAD — NOBODY STAYS.
The Tailboard firefighter anchors the hose, leaves the hydrant bucket, and proceeds to the fire with the crew. Other personnel are assigned to charge the hydrant — know who that is before you pull away.
"The back-up firefighter will remain at the hydrant and charge the line when the command to do so is received."
"The Tailboard firefighter anchors the hose, leaves the hydrant bucket, and proceeds to the fire with his/her crew. Other personnel will be assigned to charge the hydrant."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-8
Reverse lay — fire to hydrant
ARRIVE AT THE BUILDING FIRST, THEN LAY OUT TO THE PLUG.
It puts your engine at the source, so you can supplement hydrant pressure to the engine that ended up in front of the fire. Available to the first or the second due.
"The reverse lay option may be employed by either the first due engine or the second due engine and occurs when the engine arrives at the fire building first and then proceeds to the hydrant location. In some cases this action may be advantageous for the fire ground operations because it places the engine at the source of the water and the engine can supplement the pressure from the hydrant to the engine that ends in front of the fire."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-9
DECIDE WHICH SIDE OF THE PUMP THE LDH LANDS ON.
Supply evolution — LDH between the suction side of the pump and the hydrant. Attack evolution — LDH between the discharge side of the pump and an appliance or master stream.
Muscle memory
Suction side = you are feeding somebody. Discharge side = you are the gun.
"Supply evolution: LDH is connected between the suction-side of the pump, and the hydrant."
"Attack evolution: LDH is connected between the discharge-side of the pump, and an appliance or master stream."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-9
Feeding a gun? Master Stream Operations
Split lay — when your position has no water
DROP THE LDH AT THE ENTRANCE AND TRANSMIT IT.
Cul-de-sac, limited-access apartment complex, commercial structure where the water is out on the main thoroughfare. The first due must transmit the intention to start a split lay.
SECOND DUE COMPLETES THE SPLIT — EITHER DIRECTION.
Depending on their direction of travel relative to the split, they lay out from the split to the hydrant, or lay in from the hydrant to the split.
"The third option for engine companies to lay hose is the Split Lay. In this operation the first due engine may have to place their apparatus in a position where there is no water. Examples of this may include operating in a cul-de-sac or entering a limited access apartment complex or commercial structure where the water supply is located on the main thoroughfare. If the company officer chooses this tactic, they will drop their LDH at the entrance to the area that they will be operating. If the first due engine MUST transmit their intention to start a split lay."
"The second due engine will complete the split. Depending on the direction of travel in relation to the split, they can either lay-out from the split to the hydrant or lay-in from the hydrant to the split."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-11
High-flow hydrant operations — least to best preferred
MULTIPLE SUPPLY LINES FROM A SINGLE HYDRANT.
Least preferred — every line is drawing on the same barrel.
PUMP THE HYDRANT WITH THE 2ND OR 3RD DUE ENGINE SUPPLYING THE ATTACK PUMPER.
MULTIPLE SUPPLY LINES FROM DIFFERENT HYDRANTS SHARING THE SAME MAIN.
MULTIPLE SUPPLY LINES FROM DIFFERENT HYDRANTS NOT SHARING THE SAME MAIN.
Best preferred.
Muscle memory
The best water is water that does not share a main. Two lines off one plug is the answer of last resort, not the first move.
"There are three basic tactics to employ when getting the most water from a distribution system. They are listed below in order of least preferred to best preferred."
Note for the reader: the heading says three basic tactics and four bullets are printed underneath it. All four are reproduced above in the printed order.
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-13
Relay pumping — when the water is a long way off
PUMPERS IN SERIES: DISCHARGE OF ONE FEEDS THE INTAKE OF THE NEXT.
Used when the water source is remote from the fire scene. It only works with pre-planning, training and coordination of everybody in the chain.
THREE SEATS IN A RELAY: SOURCE, RELAY, ATTACK.
Biggest pump goes to the source. Relay pumpers can be smaller because they inherit the energy of the pumpers behind them. The attack pumper feeds the lines and appliances at the fire.
"Using two or more pumpers to move water over a long distance by operating them in series; water discharged from one pumper flows through hoses to the inlet of the next pumper, and so on."
"A relay pumping operation consists of a pumper positioned at the water supply source that is used to pump water under pressure through one or more supply lines to another pumper connected further down the supply line(s). This pumper boosts the pressure to supply the next pumper and so on until water reaches the attack pumper. In order to be effective, relay operations require pre-planning, training, and coordinating of all participants."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-14
OREM RELAYS ON CONSTANT PRESSURE.
Relay pumpers spaced at 750-foot intervals; source and relay pumpers hold 175 psi PDP; the attack pumper adjusts and dumps the excess.
"Orem Fire Department uses the Constant Pressure Relay method for establishing hydraulic pressures and distances during relay operations. For more specific information see the current APPARATUS DRIVER / OPERATOR HYDRAULIC CALCULATION STANDARDS in Target Solutions."
Engine Company Operations 2023 V-1, ch.5 Water Supply, p.5-15
From that standard: relay pumpers are placed at 750 foot intervals; every pumper except the source opens a discharge to exhaust air from the lines; the source pumper throttles to 175 psi, then each relay pumper closes its unused discharge once a steady stream flows and throttles to 175 psi in turn; all driver/operators set their intake relief valves; the attack pumper adjusts PDP to supply the attack lines. The 175 psi figure accounts for 20 psi residual at the next pumper in the relay.
OFD Apparatus Driver / Operator Hydraulic Calculation Standards (Target Solutions), Constant Pressure Relay — unpaginated
Full procedure: Relay Pumping
Flagged for the training committee
Engine Company Operations p.5-5 carries a pump-rating bullet and a set of outlet-flow bullets that cannot be reconciled with what the same chapter states three pages earlier about a double 2½″ hydrant. Rather than teach a number the department may have to correct, those bullets are held off this page and are on the list to take to the training committee.
The water-supply figures that are operative, and that this page teaches:
Double 2½″ hydrant — two 2½″ outlets on a 4″ main, no steamer — expect less than 600 gpm (p.5-4), and provide one 5″ supply line for every 1,000 gpm to be delivered (p.5-5).
Apparatus capacities are likewise not published anywhere on this site until they are verified at the rig and put on that apparatus's own spec sheet.
Sources: Engine Company Operations 2023 V-1 — ch.1 Firefighter Assignments (pp.1-3, 1-8 to 1-11, 1-24) and ch.5 Water Supply (pp.5-1 to 5-15); OFD Apparatus Driver / Operator Hydraulic Calculation Standards (Target Solutions, unpaginated). Page numbers are the manual's own per-chapter footers.
The manual's photo and figure references (Photos 5-1 to 5-18, Figures 5-7 to 5-13) are not reproduced here; look them up in the chapter itself.