Dry Pipe Sprinkler Systems – Inspection, Testing & Maintenance

April 14, 2012
Dry Pipe Valve

A differential Dry Pipe Sprinkler System

The next article in a series discussing fire sprinkler system inspection testing and maintenance is published in ASSE Fireline.

Inspection, testing and maintenance of dry pipe valves and dry pipe systems are critical to maintaining effective fire protection. Dry pipe valves are used in areas subject to freezing temperatures.

This article focuses on Chapter 13, Valves, Valve Components and Trim, and assumes that all items discussed in previous articles regarding valve inspection and testing, records plans and calculations and impairments to the fire system have been completed. This article discusses items that apply specifically to dry pipe valves.

A dry pipe sprinkler valve is a special valve that prevents the pressurized water in the fire mains from entering the sprinkler system piping. Normally, this is accomplished by filling the system with air. Most valves use a differential method of keeping the valve shut, and generally, the differential is 5:1 or 6:1. This means that 5 or 6 psi of water pressure is held back by 1 psi of air pressure. In the event of a fire in which a sprinkler head actuates, the air pressure in the system decreases until the valve trips. The trip pressure in a 5:1 dry pipe valve at 60 psi of water pressure is 12 psi. As the air pressure dips below 12 psi, the valve will trip, allowing water to enter the sprinkler piping and eventually exit through the open sprinkler head. A safety factor, usually about 20 to 25 psi, is maintained above the trip pressure to help prevent false trips. An air compressor, or other means of maintaining pressure in the system, is arranged to automatically maintain adequate air pressure.

Components of dry pipe valves are discussed, described, and explained. Testing procedures for properly tripping a dry valve is outlined, as well as an explanation of how to reset typical differential dry valves.

Find the article here – Dry Pipe Sprinkler Systems – Inspection, Testing & Maintenance

Find additional articles at my Articles & Presentations Page

ASSE’s 100th Anniversary

May 5, 2011

ASSE’s 100th Anniversary from jon schwerman on Vimeo.

The American Society of Safety Engineers is celebrating its 100th Anniversary in 2011. Founded in 1911 as the United Association of Casualty Inspectors, the Society was formed in the wake of tragic events such as the March 25, 1911, Triangle Shirtwaist Factory Fire in New York City where 146 young girls and women lost their lives in a workplace tragedy that drew the attention to the need for workplace safeguards and regulations.

The Beginning Of Safety Engineering As We Know It

February 6, 2011

Recently, I was asked to write about a historical aspect of fire protection and safety engineering for the Fireline, a publication of ASSE’s Fire Protection Practice Specialty. This is a synopsis of some of the information from that article and research.

Insurance engineers go back to the early 1800’s. In 1835, Zachariah Allen, a textile mill owner made property conservation improvements to his property that would help them minimize the fire hazard. At that time, he approached his insurance company for a rate reduction, and was denied. This was the formation of the highly protected risk (HPR) mutual insurance companies. Over the next 20 years, more mutual insurance companies were founded, and they joined forces to provide additional capacity for losses. These companies involved into the Associated Factory Mutual Fire Insurance Companies, or as they became known, the Factory Mutuals.

Each of these companies employed loss prevention engineer’s. By 1878, the Factory Mutuals established a dedicated unit of engineers to inspect insureds facilities. Factory Mutual (FM) began testing products in 1886. FM also had follow-up inspections at manufacturers, and, like UL, investigated failures of equipment and installations.

In 1890, about a dozen stock insurance companies join forces to write insurance for factories with too much hazard in value for any one of them to handle on their own. This was the Factory Insurance Association (FIA). The FIA maintained a dedicated group of engineers to travel the country to inspect insured facilities.

In the late 1800s, safety engineering was so prevalent that weekly newspapers was published by insurance interests under the title “Insurance Engineering.” Prior to 1913, Insurance Engineering was renamed Safety Engineering. “The Standard – A Weekly Insurance Newspaper” was another magazine which regularly had articles about safety, mostly on the fire side. At that time, most safety engineering was performed by engineers. Safety engineering in the early 1900s was an independent branch of social science which was contributed to by an increasing number of research laboratories. These laboratories are maintained by manufacturing facilities, as well as insurance company supported laboratories. During the late 1800s, the factory mutual was one of the leading sources of fire protection technology, testing, and approvals area this information was developed primarily for their shorts. Prior to 1900, stock insurance company underwriters would individually decide which fire protection equipment, and equipment arrangements they would accept.

One of the big steps towards early safety engineering and laboratory testing was at the 1893 World’s Columbian Exposition in Chicago. People were amazed by the spectacular vision of 100,000 Edison light bulbs area at this exhibition, fires kept breaking out, igniting the combustible building covering. Chicago fire insurance authorities were concerned about the network of electrical wires, and their connections, and the new alternating current. In response, William Henry Merrill, an electrical inspector, set up a laboratory near the fairgrounds, above the Fire Insurance Patrol Station Number One. This one-room laboratory was furnished with a bench, table, chairs, and a few electrical measuring devices purchased for the sum of $350. The Chicago Board of Fire Underwriters in the Western Insurance Association provided financial backing, and the Laboratory Became The Underwriters Electrical Bureau.

In 1900, the laboratory moved into larger quarters, and in 1901 it was chartered as Underwriters laboratories, Inc. Its new sponsor, the National Board of Fire Underwriters was the basis for the new name.

Insurance company offices were typically located in major cities around the US. Fire protection engineers were assigned to an office, but some, even going back to the early 1900’s were located geographically around the country. They would handle the work around their towns, and travel as needed to more remote areas. I recall speaking with older engineers who had retired from FIA, some of whom followed in their father’s footsteps. They related that the early engineers would travel mostly  by train to a town and be met by a plant employee who would provide transportation to the factory. Trips in those days could be  long, and in some cases it would be weeks before the engineer returned home.

Based upon my own personal research, I believe the current profession of safety engineering evolved from the fire protection engineers of the 1800s. Fire protection engineers had a huge head start in the safety engineering field due to the financial ramifications of fire. Workers compensation, liability insurance, and other safety aspects developed later in time. When the American Society of Safety Engineers was founded in 1911, the impetus was a fire related event in which there was loss of life.

I also believe that the aviation industry in the maritime industry drove safety engineering. Maritime safety is evident hundreds of years ago. Ship owners, and maritime underwriters had a vested interest in the safe arrival of ships and goods. While the driving force was not employee related, sailors were a valuable commodity on the ships, where there were no quick replacements. In the aviation industry, a failure typically resulted in a crash and loss of life. The military drove safety engineering, and, more recently, fault tree type analysis of which Willy Hammer wrote in his book.

The military also implemented safety engineering hundreds of years ago. In colonial Williamsburg, some of the discussions that I attended were regarding the safety of the powder magazine, and why it was located away from other buildings. Even during the Revolutionary war, there were special precautions in place for the handling of black powder and munitions. At that time, the practice was not referred to as safety engineering, but in my mind that’s what was.

In celebration of ASSE’s 100th anniversary, the Fire Protection Practice Specialty has dedicated its first issue of the year to historical aspects of fire. An article about the evolution of the fire sprinkler discusses many of the items listed above. Much of the information mentioned here is from that article, and related research. Fire protection practice specialty members will receive the entire publication within the next few weeks.

For more information, check out this article:  Evolution of the Fire Sprinkler

©Walter S. Beattie