Operations

The Design of the High-Rise Handline

Issue 7 and Volume 11.

Have you heard the saying that there is more than one way to skin a cat? This statement holds true for a lot of things in general as well as with the fire service. Yes, our main goal is to fight fire; however, there are so many different ways to do it while still reaching the final outcome. Going one step further: What about high-rise firefighting, mainly the handlines that are used? I have been teaching water delivery in the fire service for about 30 years now, and the topic of high-rise handlines has been in the picture the whole time. I’ve seen a lot of changes, and most seem to work. Some tactics and equipment contradict each other, but again the final outcome is that the fire gets extinguished. I have put together some sound handline water delivery operations along with the proper equipment that I feel gets the job done. This article is based on information gathered from others as well as myself. Keep in mind that the contents of this article are based on water delivery only.

My goal is to provide information that will help firefighters make a decision on what size handline to deploy in a high-rise fire. There are four basic components for a high-rise handline operation. They are the hose, the nozzle, a 2½-inch × 2½-inch gated wye, and an inline pressure gauge.

NFPA 14

Choosing the proper hose and nozzle combination needs to be based on delivering the required flow for fire attack using low system operating pressures. The reason for this is simple: High-rise fire protection systems are limited in operating pressures because of elevation; friction loss in plumbing; pressure reducing devices; and, probably the most concerning issue, system pressures established by National Fire Protection Association (NFPA) 14, Standard for the Installation of Standpipe and Hose Systems, which is the code that high-rise fire protection systems are designed from.

There are two basic sets of standards that have been put in place by the NFPA that can affect water delivery. The first standard was in place until 1993 and the second standard, which is still in place, started in 1993. Please note that structures with the pre-1993 standards were not required to upgrade to the post-1993 standards.

Pre-1993: The minimum requirement for water delivery is 500 gallons per minutes (gpm) at 65 pounds per square inch (psi) standpipe outlet residual pressure using two outlets to achieve this flow at the highest point in the system, or what the NFPA refers to as the hydraulically farthest outlets from the building pump. The pressure regulating device at the standpipe outlet has a maximum pressure setting at the standpipe outlet of 100 psi under static and residual pressures.

Post-1993: The current code requires the same 500-gpm flow but the minimum standpipe outlet residual pressure was increased to 100 psi and the pressure regulating device at the standpipe outlet was increased to have a maximum setting of 175 psi under static and residual pressures.

Pressure Issues

Because of the above-mentioned pressure issues in fire protection systems, most fire departments have opted to exclusively use 2½-inch handlines with smooth bore nozzles for all fire scenarios, big and small. The fact is that the 2½-inch handline will provide the most water every time. However, along with the positive flow capabilities of this line, there are also negative deployment and kinking issues that have to be dealt with because of the size of the hose itself.

The low standpipe outlet pressures mentioned above have been misleading, causing firefighters to assume that smaller handlines such as 1¾-inch and two-inch could not be used because of the higher friction loss these lines have as compared to the 2½-inch. Let’s analyze the true pressures that can be expected in a high-rise fire protection system.

High-Rise Fire Protection System Handline Flow Tests

8/24/15: Riviera Hotel, Las Vegas, Nevada

System Specifications: 500 gpm @ 65 psi SORP

COMBAT READY

1.88-in. hose × 150 ft.

SORP 85

GPM 165

TIP 7⁄8 in.

NP 54

SORP 85

GPM 185

TIP 15⁄16 in.

NP 50

SORP 85

GPM 210

TIP 1 in.

NP 50

SORP 85

GPM 218

TIP 11⁄8 in.

NP 34

ECO 10

2-in. hose × 150 ft. with 2-½-in. couplings

SORP 85

GPM 177

TIP 7⁄8 in.

NP 62

SORP 85

GPM 201

TIP 15⁄16 in.

NP 60

SORP 85

GPM 217

TIP 1 in.

NP 54

SORP 80

GPM 248

TIP 11⁄8 in.

NP 44

BIG 10

2½-in. hose × 150 ft.

SORP 80

GPM 265

TIP 11⁄8 in.

NP 50

SORP 75

GPM 345

TIP 11⁄4 in.

NP 56

SORP: standpipe outlet residual pressure GPM: gallons per minute NP: nozzle pressure

NOTE: Tests were done from the hydraulically farthest standpipe outlet from the building pump.

Flow Tests

Again, fire protection systems are based on a 500-gpm flow capability, and after flowing 500 gpm the standpipe outlet residual pressure will need to be either 65 psi or 100 psi, depending on when the system was built. The fact is that if 500 gpm is not flowing, which more than likely it would not be with the initial handline deployment, the standpipe outlet residual pressure will actually be higher (as can been seen in the handline flow tests image).

Actual flow tests were conducted at the 25-story Riviera Hotel in Las Vegas, Nevada, using 1.88-inch, two-inch with 2½-inch couplings, and 2½-inch hose-all at 150 feet in length. All hose was provided by Key Hose. We used smooth bore nozzles with 7⁄8-inch, 15⁄16-inch, one-inch, 11⁄8-inch, and 1¼-inch tips to deliver the water. The flow tests were done on the roof to show a worst-case scenario of what the pressures and flows would be. The system was rated at 500 gpm with a 65 psi standpipe outlet residual pressure.

As you can see, the standpipe residual pressures increased significantly from the rated 65 psi pressure. Furthermore, all flows exceeded 150 gpm, which is well within the standard for interior attack lines. Keep in mind that the 65 psi system we tested these lines on is a worst-case scenario with regard to NFPA codes and restrictions. Any structure built after 1993 will have the 100-psi standpipe outlet pressure, which in turn means that the handlines will flow even more water. As a side note of interest, the authority having jurisdiction in Clark County, Nevada, has increased the required residual pressure at the standpipe to 125 psi after flowing the required 500 gpm.

The size of the hose to be used should reflect the requirements of the fire and the system pressure. The gpm needs to match the British thermal units, and the diameter of the hose needs to be able to overcome the system low pressure issues. Note: To have the luxury of an easy-to-deploy 1¾-inch or two-inch handline, it is imperative that a 2½-inch hose pack be brought into the structure just in case its use is warranted.

Low-pressure nozzles are a must in a high-rise operation even with the higher residual pressures, which were indicated in the chart. Remember, system pressures are going to be low, so lowering the nozzle pressure from the standard 100 psi to a much lower pressure in the range of 40 psi to about 60 psi greatly improves water delivery capabilities.

It’s important to understand that these flows were taken at the roof, which is a worst-case scenario for pressure loss in the system. The lower you go in the building, the higher the flow and nozzle pressure will be.

Standpipe Connections

Not all standpipe outlets are user-friendly with regard to connecting hose and gated wye appliances to them. Because of this, a short 15-foot section of either 2½- or three-inch hose should be used to connect the high-rise pack to the standpipe outlet.

A 2½-inch × 2½-inch gated wye: This should be connected to the end of the short section of hose leading from the standpipe to allow two handlines to be connected from one standpipe outlet. Flow tests at the same structure gave us a flow of 238 gpm each from two 2½-inch handlines 150 feet long with 11⁄8-inch smooth bore tips.

A 2½-inch inline pressure gauge: This is connected between the gated wye and the short section of hose leading off the standpipe outlet. Its purpose is twofold: Part of the high-rise deployment procedure requires a flow test of the handline before commencing with the fire attack to determine if the required handline pressures can be met from the system, which in turn will help decide what size line can be used. It also helps to dial in the required pressures for the handline.

For example, let’s say you’re using Combat Ready 1¾-inch hose and the required pressure for that line to flow 185 gpm with the 15⁄16-inch smooth bore is 105 psi. This can be noted with a label on the side of the gauge body so if an adjustment is needed at the standpipe a firefighter simply adjusts the standpipe outlet valve to the required pressure.

Best Decisions

I hope this information has been helpful in providing a better understanding of what is involved with water delivery in a high-rise fire protection system. Basic decisions in the size-up on the fire floor are crucial in making the correct choice for the handline to be used. Remember: There is more than one way to skin a cat, so if you agree with the information provided but feel a need to tweak it for your department’s operations, then by all means make the changes so you will have a system that works best for you.