links & chemical


Recently a fire protection guy told us never to get chemical on the fusible links. We have seen chemically cleaned links for a decade without any incident. Called a supplier (Bonzi) and was told to hit the links, let it cook, and rinse well. Anyone had any problem with links resulting from chemical application?


I have had no problems with the links, I have also been told not to get chemical on the links. When I asked the guy how not to get chemical on the link he said and I quote " that is not my problem". I think the idea is that the repeated chemical abuse may weaken the link causing it to release prematurely, but if they are replaced periodically I would think that would prevent that problem.
This is a question best answered by those of you who do both the suppression and the cleaning. How do you deal with it?
I did have a system go off after we had finished cleaning, had the equipment back in place and were about to leave, none of the links were broken and to this day no one can tell mw why it went off. It cost me $ 2200 before it was over

Ron Musgraves

Exterior Restoration Specialist
Staff member
I'm not a hood cleaner but i would say those links are plastics resins. they wont mix with caustics.

I could be wrong on this, wait for Grant, matt or David..


The links are metal with a solder like "glue" holding them together. The melting point of this solder is the rating for the link. Most are 450 degrees in restaurant applications (except Burger Kings @ 500 degrees) Most chems would have little or no effect on them. However, the highpressure blasting, while not affecting the link itself, can and sometimes will cause enough slack in a tight line to set the system off. Still the best thing to do is treat them as fragile... avoid chems if possible and light pressure.
But keep in mind the links are required by NFPA 96 & NFPA 17 to be changed at least annually or as required by the manufacturer. PS. every manufacturer requires them to be changed at least every six months.
So dont hit 'em with 4500psi 0 degree tips Okay
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Interesting to know, I heard or thought that they just had to be inspected, Not changed every 6 months... Plus would the fire suppression tag indicate the service and replacment of such...
Would they change just the link or do they change link and cable...

I was so interested in this thread I looked up this answer myself, I am going to stick my foot in my mouth on this one but here it goes... 8-3.5 says that care shall be taken not to apply cleaning chemicals on fusible links or other detection devices of the auto extinguishing system... Plus there is a exception to the 8-2.2 rule that where automatic bulb-type sprinklers or spray nozzles are used and annual examination shows no buildup of grease or other materials on the sprinkler or spray nozzles...So to me it say if they kept their hood cleaned, They would not have to have this done every 6 months if properly cleaned...Confusing, Please correct this rookie...

Thank you and sorry for being so long winded...

Rookie in Iowa Matt
Fusible Links are to be replaced as per the mfg specs
Amerex @ 6 months intervals
Ansul 12 month ( but recommend evry 6 months)
Kiddde 6 months
Range Guard 6 months
Pryo Chem 12 month

Fusible links have the following info stamped on them:
1. the year manufactured
2. the temp rating
3. the model number (K, ML, A, B, D from Globe , or Elsie A)

Automatic bulb type detectors are the glass bulb type. These are either detectors for suppression systems or sprinkler heads. If these are kept clean, they supposedly never need replacement. Of course you do not want to hit the glass bulb. If you break the glass, the suppression system will activate.

As a further note, Ansul notes in the installation manual that the cable crimps ( found on the detector cable at the end of line detector and somtimes the series detector ) are not to be made of zinc, but brass instead. The zinc cable crimps are subject to corrosion when in contact with cleaning chemical. This can lead to un-wanted system activation. Remember this when you get blamed for tripping a system. The crimps should be made using only the correct tool, which is not vise-grips.

Fusible links come in different temperature ratings, from 135 F to 500 F. Mc Donalds specifies low temp links in some of their applications. Links also come in different load rating ranges, 3 # to 50 #. Amerex allows only K links in their systems.

Not all installations have the detectors/conduit properly secured. Loose parts may be the cause of un-wanted activations. If you find these problems, make notes, CYA.

Keep on the good side of a fire protection company, that way should you get blamed for an un-wanted system activation, you can call in your expert witness. May be the fault is not yours, but the actions of someone else. Or maybe it is your fault, it happens. When I was learning fire suppressions systems, I was told I could not claim to be an expert untill I tripped a sytem. In 24 years, I have tripped 3 systems. It was embaressing, but I made it right and kept my customers.

Douglas Hicks
General Fire Equipment Co of Eastern Oregon, Inc


Thank you Mr. Hicks,
The rules that we follow are and can be confusing... Myself, Being new to exhaust cleaning, Need some guidence on cleaning, stardards, and codes... I want to salute all exhaust cleaners for the help I have recieved in the past and in the future to my questions...

Thank you!!!