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NFPA 25 (2020) notes that standard response sprinklers are to be tested or replaced after 50 years in service, and quick response sprinklers after 20 years in service.
An issue arose regarding standard response 5mm glass bulb recess sprinklers installed / manufactured in 1990. The heads are RASCO Model F156. The data sheets note standard response. My understanding is that these sprinklers, being standard response, should have a 15-year service life before testing. Others in the trade have different opinions (including a manufacturer rep) due to the operating element being a glass bulb. Prior to contacting the manufacturer, I'd appreciate the forum's thoughts on whether the glass bulb or the fusible link is a determining factor in the required time for sprinkler testing. Thanks! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
6 Comments
Dan Wilder
9/2/2025 08:35:30 am
Depends on your adopted year (you stated 2020), the glass bulb type, and the wording (element vs sprinkler), location of the sprinkler (adverse conditions). Some reference the element, some just the sprinkler type. MFG requirements supersede NFPA 25 when more restrictive and/or approved by the AHJ but I'm not sure I have seen any data sheets being more restrictive for sprinklers. 2025 references back to 13 for the definitions. "Typically," a 5mm bulb has been standard response.
David Kendrick
9/2/2025 08:36:34 am
For directions about sprinkler head inspection and testing opinions are secondary to the applicable NFPA 25 that is in force for the location of the system(s) being surveyed.
Brian Gerdwagen FPE
9/2/2025 08:55:58 am
I trust links less than bulbs. When a bulb gets close to its operation temperature, but does not surpass it, and cools back down, nothing happens. With a link, I have seen the solder get soft and migrate due to gravity. I have been involved in a couple inadvertent discharges with links where the links around the activated sprinkler looked like the solder was about to drip off the link. Glass bulbs may be more delicate, but as long as the liquid stays in the bulb, they are more resistant to time.
chad
9/2/2025 11:00:03 am
That is fascinating..... did the sprinkler manufacturer weigh on this? Just curious.
OP
9/2/2025 10:32:22 am
Additional info. Date of head manufacturer is 1990, Assumption was made that heads were installed also in 1990 (conservative approach) Wet pipe sprinkler system in a hospital. RTI was not noted on Reliable's data sheet, but 5mm and standard response was clear.
Jack G
9/3/2025 04:57:05 pm
A specific load screw with a manufacturers secret torque is used in the manufacture of bulb sprinklers in conjunction with a Bellville spring and plug that prevents water from discharging. Leave a Reply. |
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