Everything You Wanted to Know About Fire Sprinklers (But Were Afraid to Ask)

Fire sprinkler systems have been a hot topic for several years in Hawai’i after the infamous Marco Polo fire in 2017. Honolulu’s mayor at the time wanted to require sprinkler systems in every residential high-rise building, but cooler heads prevailed and the Honolulu City Council passed a bill giving every residential high-rise a way out.

Or so we thought.

There’s still a way out of having to install fire sprinklers, but there’s also extreme pressure being exerted on condo owners to put them in. Both the Honolulu Fire Department and the insurance industry are pressing for it.

Although our company, Douglas Engineering, is not inherently anti-sprinkler, we’re against bullying tactics designed to scare people into spending money they don’t have.

A fire sprinkler system is a big investment and may be just what a building needs…or not.

HOW DO THESE SYSTEMS WORK?
Fire sprinkler systems are pressurized water piping systems with heat sensitive heads that distribute water onto the heat source that activates them. Due to this technology, only one or two heads might actually spray water during most fires.

The system also includes a pump, which automatically starts up when a drop in pressure is recognized. The pump and piping are designed to maintain a certain flow rate at a certain pressure at the most hydraulically remote area in the building.

For a high-rise building, this equates to the demand for four sprinklers in a corridor and a maximum of four sprinklers in an apartment on the top floor. Of the fires we’ve investigated, however, the sprinkler systems only activate one head, which is still enough to extinguish the blaze – while also causing millions of dollars of water damage.

WHERE ARE SPRINKLERS REQUIRED?
In new construction, fire sprinklers are required in every space of a building. But when it comes to existing residential structures, the Hawai’i ordinance that guides installation doesn’t require fire sprinkler heads on some lanais, in bathrooms less than 55 square feet in size, inside closets and pantries less than 24 square feet in size, or in elevator shafts constructed of non-combustible materials.

INSTALLING FIRE SPRINKLERS
Installing a system like this in an existing building is not an easy task. It’s not just a matter of hooking up to an existing water supply. A separate fire connection to the street with a separate water meter is needed.

Piping from that separate connection will go to a fire pump, followed by a riser that goes from the bottom to the top of a building. That riser will then branch off on every floor and run down every hallway before branching again into every unit’s living area (excluding bathrooms, closets, and lanais exempt under the ordinance).

The fire pump is a major component in the system and is either powered by the building’s standby generator or will be diesel-powered with its own fuel source on-site.

A building’s existing standby generator will mostly likely not be large enough to handle a 100-horsepower pump, in which case a decision will have to be made to either upgrade the generator or use a diesel-powered pump. This decision should be guided by a mechanical/electrical engineering consultant.

USING EXISTING FIRE SYSTEMS
Existing fire hose cabinets cannot be used to connect sprinkler piping for each floor because the riser pipes feeding them are too small.

Instead, an existing dry standpipe located in a building’s stairwell can be converted to a wet standpipe, with horizontal piping and zone control valves/flow sensors connected to it.

But if the dry standpipe is original to the building, it may be a better idea to replace it while also conducting a fire sprinkler retrofit.

COMMON SPRINKLER PIPE ALTERNATIVES
There are a few options when choosing fire sprinkler pipe material. Which one should your building use?

Traditional iron pipe, galvanized iron pipe, copper pipe, and chlorinated polyvinyl chloride (CPVC) pipe are all acceptable options for a fire sprinkler system.

CPVC pipe is billed as a lower-cost alternative, but our experience with this material is that it’s inferior and doesn’t save much money, if any. 

Labor is always the deciding factor in the total cost of a job like this. CPVC is touted to save labor, but contractors don’t seem to be passing those savings on to the customer. It seems like good old copper pipe is still the winner for branch piping, with galvanized iron recommended for larger sizes.

WHAT ABOUT EXPOSED PIPE?
The exposed pipe down a building’s corridor can be covered with soffits (box-like structures made of drywall that enclose and hide pipes running along the ceiling or walls).

We typically see soffits installed symmetrically on both sides of a building’s interior corridors, with crossover soffits added to create an architecturally pleasing experience. Most buildings also combine new corridor lighting with soffit installation.

Individual units will also have soffits that cover exposed pipes, which will likely run along the wall near each unit’s entry doors with one head for the kitchen, one for the living room, and one for each bedroom.

ASBESTOS CONCERNS
All remodel projects are required to have asbestos testing of at least three samples per floor, or the drywall, mud, and popcorn ceiling must be assumed to include asbestos containing material (ACM).

If a building is old enough to be covered by this ordinance, it will have ACM. This adds another dimension of complexity and cost to the project. All holes cut and all soffits constructed will require work from a qualified asbestos abatement contractor.

OVERALL COSTS VARY
Project costs vary greatly in Hawai’i. The availability of contractors and materials doesn’t affect other locations the same way it does here in the islands.

The projects our firm has been involved with are seeing costs averaging between $35,000 to $40,000 per unit. That’s a far cry from initial estimates by HFD and other “experts” who predicted it would cost between $5,000 to $12,000 per unit to install fire sprinklers.

The data could change, as there haven’t been a lot of these projects completed yet, but our expectation is costs will remain at these levels due to Hawai’i’s remote location and limited competition.

THE MORE, THE MERRIER?
Some experts recommend combining fire sprinkler and plumbing waste piping replacement projects. Our firm believes this may not actually make the most sense.

The waste piping within the walls of a unit is vertical, and one stack usually services two units per floor.

Sprinkler piping, on the other hand, distributes horizontally per floor and runs along the ceiling. There simply is nothing in common between a waste pipe replacement and a sprinkler system installation.

We’ve confirmed with our contractors that the only advantage to combining these projects might be a savings in the mobilization fee. This certainly won’t amount to the millions of dollars some might claim buildings could save by combining projects.

The best way to save money is to be sure you have the right bidders on your list and carry out one project at a time. This eliminates any need for coordination between projects and complex project management.

Even our clients who have seemingly unlimited funding are taking this approach.

AVOID COSTLY MISTAKES
A fire sprinkler system is a big capital investment. While it does add an extra measure of protection to a building, firefighters, and its occupants, the installation of a new system in an existing building will undeniably be both expensive and disruptive.

All construction projects require hazardous materials testing and most likely abatement during the project, so a licensed mechanical/electrical engineering company should be hired to assist with a complex and important project such as this.

A reputable firm will employ trained and licensed professionals that can guide buildings through the process and help associations avoid costly mistakes.