BY DANIEL SHERIDAN
Standpipes may be found in shopping malls; theaters; and residential, large commercial, and public assembly buildings. There are two types of standpipe systems, wet and dry. Wet systems have water in them all the time and are usually supplied by a gravity tank or a water main. Dry systems are usually found in parking garages or other areas that may be subject to freezing.
In the Fire Department of New York (FDNY), our standard operating procedure (SOP) for working in buildings with standpipes is to supply the fire department connection (FDC) or siamese with the largest diameter hose possible, which in FDNY is a 3½-inch hose.
(1) Fire department connection (siamese). (Photos by author.)
We should always be ready to supply the system if needed, especially if the building does not include a fire pump or has inadequate standpipe pressure. The pump discharge pressure for each hoseline attached to a standpipe outlet should be 100 pounds per square inch (psi) plus five psi for every floor above the first based on two lengths of 3½-inch supply and three lengths of 2½-inch hose attached to the outlet using a 11⁄8-inch smooth bore nozzle (see “Supplying the First-Floor Outlet”).
On a recent day tour, I took the crew out to look at one of our fire-resistive buildings. The 19-story building has two 7,500-gallon gravity tanks on the roof that supply the standpipe; it does not have a fire pump. This system also supplies the building’s domestic water needs. We wanted to check the different pressures on various floors without charging the system.
The first-floor standpipe outlet included a pressure gauge, which indicated about 100 psi, which in theory would be more than enough pressure to operate a 2½-inch hoseline. We attached one length of 2½-inch hose with a 11⁄8-inch smooth bore nozzle.
When we opened the outlet, the pressure dropped dramatically to 45 psi. We had a decent stream but not enough to fight a fire if we had to.
We made our way up to the 19th floor; again, we checked the pressure. It was zero. We stretched a line up to the roof; we had barely enough water to put out a small trash fire. In this building, we would need to supply the system from a fire department pumper to fight a fire.
One situation that pops up from time to time is closed sectional valves. About a year ago, we responded to a report of fire on the 10th floor of a 19-story fire-resistive multiple dwelling. The dispatchers were getting a few calls, and it sounded like we were going to go to work. We took the elevator to the eighth floor. From there, we walked up to the 10th floor and found smoke pushing out around the closed fire apartment door.
I had my crew get ready to hook up to the standpipe on the ninth floor. We chose the A stair as our attack stair. I went up to the 10th floor, got a look at what we were facing, and determined that it smelled like someone had left an aluminum pot on the stove. I had the guys stretch up to the 10th floor. We could stretch the line dry to the fire apartment door because the truck personnel were still forcing the heavily fortified door.
(2) Note that in this photo the valve is open. If the stem (arrow) were not visible, that would indicate the system is closed.
My crew was ready, and I asked my hookup firefighter on the ninth floor to send me water. He responded that there was no pressure in the standpipe. I radioed down to the pump operator about the situation. We had some time because the door had about five locks on it and every one of them was engaged. Finally after a few minutes, the pump operator figured it out and sent us water. It turned out that the building maintenance people were working on the system and closed the sectional valve, which prevented us from supplying the system. My pump operator resolved it by finding the valve and opening it. Had he not, there was another solution. Sometimes the siamese or FDC is impossible to supply for any number of reasonsdefective clapper valves, swivel threads out of round, or debris jammed into the siamese. But there is an alternative: You can bypass the siamese or FDC and go right to the first-floor standpipe outlet. This technique will not work on many types of pressure regulating hose valves. These types of valves allow water flow in only one directionout of the hose valve, not in.
(3) Supplying the first-floor outlet will bypass any obstructions.
When I first came to FDNY, it was common practice for the engine pump operator to bypass the siamese FDC altogether and supply the first-floor outlet because, more often than not, the siamese would be vandalized.
DANIEL SHERIDAN is a 22-year veteran of the Fire Department of New York and captain of Engine Company 46. He is a national instructor II and an instructor at the Rockland County (NY) Fire Academy. Sheridan founded Mutual Aid Americas, which works with fire departments in Latin America.
Supplying the First-Floor Outlet If FDC Defective
Assume that the standpipe outlet is 2½ inches and you are stretching a 3½-inch supply line. You have two problems right from the start: hose size and sex. You will need two fittings: a 3½-inch to 2½-inch reducer and a 2½-inch double female coupling. This technique will not work on many types of pressure regulating hose valves. These types of valves allow water flow in only one directionout of the hose valve, not in.
- 1. Stretch the 3½-inch supply line to the first-floor outlet.
- 2. Attach the 3½-inch to 2½-inch reducer to the male end of the supply line.
- 3. Attach the 2½-inch double-female coupling to the 2½-inch reducer.
- 4. Remove the outlet cap.
- 5. Attach the supply line to the first-floor outlet.
- 6. Charge the line to the adequate pressure (see “Calculating Pressure Needed” below).
- 7. SLOWLY open the valve on the first-floor outlet.
Calculating Pressure Needed
The pressure needed is 100 psi plus five psi for each floor above grade, considering that we are using three lengths of 2½-inch hose and a 11⁄8-inch smooth bore nozzle. We would hope to have 70 psi at the standpipe outlet for three lengths. If we need four lengths, then the pressure should be 80 psi.
Example: The fire is on the 11th floor. The pressure needed is as follows: 100 + 50 [5 psi × 10 floors above grade] =150 psi.