Chief Brunacini’s impact, Sprinkler Head Flex Drops

Chief Brunacini’s impact far-reaching

Chief Bobby Halton’s well-chosen words in the Editor’s Opinion (December 2017) on Chief Alan Brunacini are well-appreciated. “Great” seems to miss the mark when describing his impact on our chosen craft.

I had the opportunity to meet him once—as a matter of fact, I was standing right there when the picture used for the article later in that issue was taken. I have never been starstruck, but it is a professional moment I will always treasure—Chief Halton, Chief John Norman, Chief Brunacini, and the few minutes each gave to answer my question. Thanks to them for sharing their insight. Priceless.

By the way, Chief Brunacini has had an impact on the culture I have instilled in our five-year-old department. Take notice of our mission statement: “Be Safe, Be Successful, Be Nice.” Chief Brunacini left his mark on me as well, and I hope to keep his spirit alive in our department and chosen craft. 

Jamie Luffman

Chief

Mt. Juliet (TN) Fire Department

Sprinkler head flex drops: clarification

This is in reference to “Construction Concerns: Sprinkler Head Flex Drops” by Chief Gregory Havel (http://www.fireengineering.com/articles/2017/12/construction-concerns-sprinkler-head-flex- drops.html), with which I have a few issues.

1. On page 2, he states that the sprinkler head is preattached to the flex head. That is not correct and should require full-pressure testing of the entire pipe at the time of inspection and, in my opinion, without the heads. If I were a field inspector, I would question why they are preassembled because of the potential damage to the head.

2. On page 4, he states that the friction loss for the flex head pipe is about the same as two elbows. This also is not true. For example: a one-inch black steel pipe drop, 24 inches long with two 90° elbows, would be a total of four equivalent pipe lengths (two each) for the elbows, which is how we calculate the friction loss of elbows and tees, plus the two feet of pipe would be a total of six feet to calculate. With a flex drop, the tables provided show that 22 feet for unbraided pipe should be calculated. For braided, 24 feet (28-inch length, as there isn’t a 24-inch length for the company I checked). If the sprinkler system is required to follow FM standards, the equivalent pipe lengths are even greater, sometimes doubled.

Other sizes and companies are true to form. Equivalent pipe lengths are significantly different. So, when flex pipe is used, it needs to be known. If an inspector in the field sees flex pipe and no cut sheets for flex pipe, that is a big red flag. That information is needed to determine if the friction loss through the pipe was figured into the calculations, as it will have a significant effect on the reliability of the system. It is also necessary to verify that the pipe does not have more “elbows” (called “90° turns”) than the listings allow.

Jackie de la Osa

Fire Plan Examiner

North Collier (FL) Fire Control

& Rescue District

Gregory Havel responds: Thank you for your detailed review of my article. The article stated that the sprinkler heads were preattached to the flex drops. The heads and flex drops were assembled at the sprinkler contractor’s shop with the approval of the inspector, for better quality control, before being transported to the job site. This is the same reason that cutting, threading, grooving, and welding of sprinkler pipe assemblies are frequently completed before delivery to the job site. Pipe work and installation of threaded fittings can be done more quickly and with more consistent quality under controlled conditions in a shop than in the field. 

Fully pressure testing the pipe at the time of inspection without the sprinkler heads installed is contrary to standard practice in most jurisdictions. The practice is to hydrostatically test the entire assembly including sprinkler heads. After the testing is completed, the water pressure in the system is reduced, the control valves are opened, and the system is operational.

Standard practice by many sprinkler contractors is to conduct their own test of the system on the day before the test at which the inspector will be present so that any leaks or other deficiencies can be corrected. These sprinkler fitters and contractors will note the locations and types of deficiencies and discuss them with the inspector during the hydrostatic test, as well as the procedures used in correcting them. This can reduce the time the inspector needs to dedicate to the inspection and reduces the probability of having to reschedule the inspector because of a serious problem. 

In the 2016 edition of National Fire Protection Association (NFPA) 13, Installation of Sprinkler Systems, it states in Section 9.2.1.3.3: “Listed flexible sprinkler hose fittings and their anchoring components intended for use in installations connecting the sprinkler system piping to sprinklers shall be installed in accordance with the requirements of the listing, including any installation instructions.” The installation instructions from both the sprinkler head and flex drop manufacturers at this construction job site allowed preassembly with approval of the authority having jurisdiction. 

In Section 25.2.1.8, it states: “When systems are being hydrostatically tested, tests shall be permitted to be conducted with pendent or horizontal sidewall sprinklers or plugs installed in fittings. Any plugs shall be replaced with pendent or horizontal sidewall sprinklers after the test is completed.” As the NFPA codes and standards are usually read, this choice is to be made by the authority having jurisdiction (the inspecting official), guided by any exceptions from or additions to the NFPA standard that have been made by state statute, administrative rule, or local ordinance.

In Annex A, Section A25.2.1.8, it also states: “When a hydrostatic test is performed with plugs installed in lieu of pendent or sidewall sprinklers, a second hydrostatic test should not be required after the installation of sprinklers.”

In Section 25.2.1.1, it states: “Unless permitted by 25.2.1.2 through 25.2.1.5 [which do not apply in this case, as this installation was new construction of a single-story in a heated space], all piping and attached appurtenances subjected to system working pressure shall be hydrostatically tested at 200 psi (13.8 bar) and shall maintain that pressure without loss for 2 hours.” This hydrostatic test pressure is 33.3% higher than the 150-psi operating pressure recommended by NFPA for this type of sprinkler system. Since the steel pipe in this kind of system is capable of withstanding higher pressures and the sprinkler heads and flex drops are designed and tested for higher pressures (300 psi from some manufacturers), there is low probability of the test causing damage to the piping or heads unless they were defective when shipped from the manufacturer. 

I agree that the sprinkler manufacturer’s tables for determining the friction loss in tees and other pipe fittings must be followed and that the bill of material provided by the sprinkler system designer must include such devices as flex drops if they are used in the system. Substitution of fittings and flex drops for straight runs of rigid pipe will negatively affect the way that the system will function during water flow.  

You are correct in that 22 feet of pipe is the equivalent of two 24-inch unbraided flex drops instead of the equivalent of two 90° bends. The tables you consulted match the tables from the manufacturer of the flex drops shown in the photos, which also state that the tables are based on no more than 270° of bend (equal to three 90° bends) in the flex drop. I assumed during my original research that the information given in a technical bulletin (equivalence to two 90° bends) matched the system designer’s tables, which it did not. This error is entirely mine. I have requested that the editors make the necessary correction to the Web page and the PDF version.

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