The Authoritative Source for Plumbing, Hydronics, Fire Protection and PVF
TMB - Plumbing Engineer - Features: May 2007: Waterflow Alarms

Making a Case for Local Waterflow Alarms

By James Mikkila

The single-family residential market is continuing to grow at a rapid rate. Especially now, as national codes (e.g., NFPA 1, NFPA 101 and NFPA 5000) are in place to mandate fire sprinklers in single-family homes. In addition, many communities are mandating the use of residential sprinklers, and developers are offering fire sprinklers as an optional upgrade.

The adoption of the aforementioned codes enables the fire protection community to tackle the high number of fire-related deaths that are occuring in single-family homes. Smoke detectors help to alert building occupants to the dangers of fire. However, the next step is to implement a more-balanced system -- one that includes both smoke detectors and fire-sprinkler systems. Such a combination will ultimately save more lives.

NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes, details the installation requirements for fire-sprinkler systems in the above occupancies. However, NFPA 13D allows contractors to eliminate a key piece of equipment that is found in all commercial, industrial and multifamily residential buildings which require fire-sprinkler systems -- the local waterflow alarm. NFPA 13D states, "local waterflow alarms shall be provided on all sprinkler systems in homes not equipped with smoke detectors in accordance with NFPA 72, National Fire Alarm Code." However, NFPA 13D figures that show preferred and acceptable water supply arrangement include the installation of waterflow detectors in the piping schematics.

This means that any home that has smoke detectors installed in accordance with NFPA 72 does not need local waterflow alarms. How many new homes do you know of that do not have smoke detectors installed?

Now, to understand why such an important piece of equipment is not required, we must look at the original concept for NFPA 13D. When the standard was developed, a primary goal was keep the cost of the fire-sprinkler systems low. NFPA 13D states that fire sprinklers are not required for certain rooms that have a low statistical incidence of fires. The exception for local waterflow alarms was also allowed with the thought of keeping the cost of the installed fire-sprinklers systems low. The cost of providing a local waterflow alarm is typically $100 installed. If it sounds like a very small percentage of the cost of a new home -- it is.

Saving money on a fire-sprinkler system installation makes sense provided that the cost savings are not incurred by eliminating important functional features. The local waterflow alarm, installed in conjunction with a wateflow detector will indicate when a fire sprinkler is discharging water to control a fire. It will also indicate an inadvertent discharge of water if the piping system is damaged.

Without the local waterflow alarm and waterflow detector, who will hear the alarm? Will your neighbors know that there is a fire in your home? Will the fire department be notified to respond? In addition, water could flow for a long time unnoticed in an unoccupied home or when residents are on vacation. Water damage from a broken pipe could cause a great deal of damage to your home. Local wateflow alarms would, in most cases, alert someone to the flow of water in the home and help prevent more damage to your home and possessions.

NFPA 13D allows the contractor to install stand-alone fire-sprinkler systems or multipurpose systems that combine the piping for fire sprinkler and domestic plumbing usage. The waterflow detectors that are used for each type of piping system are different. A stand-alone fire-sprinkler system uses a standard waterflow detector that is found in all commercial, industrial and multifamily residential buildings that require fire-sprinkler systems. A multipurpose system will use a wateflow detector that will alarm on a single fire sprinkler operation, but not during normal household water usage.

A stand-alone fire-sprinkler system uses a standard waterflow detector that indicates waterflow in the system at or below 10 gpm, and if used in a multipurpose system, could send an alarm when water is being used for domestic purposes. This would prevent the fire department from arriving at your home while you are running the dishwasher or taking a shower.

A multipurpose system uses a special waterflow detector that is preset to operate at between 11 and 13 gpm. It is designed for use where the most remote fire sprinkler will flow at a minimum rate of 11 gpm. The typical domestic waterflow demand should not exceed this preset range for an alarm condition. The multipurpose wateflow detector also provides an adjustable delay device that minimizes false alarms caused by pressure surges or short periods of water use above 11 gpm.

There are many types of piping materials and joining methods that a contractor can use to lower material and installation costs. There are also specialized fittings, hangers and pieces of equipment that reduce labor and installation costs. A multipurpose residential riser is one piece of equipment that includes the pressure gauge, drain connection and waterflow detector in one unit. The riser is completely assembled and includes the waterflow detector that is specifically listed for use in multipurpose fire-sprinkler systems. The riser is made of stainless steel, is cULus Listed and also NFS approved for potable water use.

I hope you understand the need to include local waterflow alarms in your installations. Lower installed costs do not always make sense, especially when the lives of many individuals that live in single-family homes are at risk. Don't install NFPA 13D fire-sprinklers systems without the addition of local waterflow alarms and waterflow detectors. Otherwise, who will hear the alarm?

James Mikkila has been actively involved in the fire protection industry for nearly 30 years, with experience in both the fire sprinkler and fire alarm industries. Mikkila joined Reliable Automatic Sprinkler Co. in July of 2006, and is actively involved in educating the engineering community about the benefits of using Reliable's products. He earned an undergraduate degree from Ohio University in Business Administration and an M.B.A. from Baldwin-Wallace College.

Plumbing Engineer Twitter
Digital Editions
Timothy Allinson
Designer's Guide
Sam Dannaway
FPE Corner
Ron George
Code Update
Winston Huff
Sustainable Design
Bristol Stickney
Solar Solutions
Joseph Messina
Engineer's Notebook
Max Rohr
Alternative Energy
2014 Sponsors