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Glass Bulb Sprinklers

Grinnell Quartz Bulb 1931

I’m sure everyone is familiar with glass bulb fire sprinklers. So much so in fact that they may not be familiar with fusible link sprinklers. The glass bulb is considered the standard type of sprinkler operation today. But, us older folks in the sprinkler community remember a time when the fusible link sprinklers were the standard. But did you know that the glass bulb sprinkler has been around over 80 years!

Grinnell Quartzoid C 1952

Grinnell introduced the first bulb in 1921 known as the Quartz Bulb. It is described in the 10th edition of the NFPA Handbook as a silica bulb sprinklers and as late as 1948 still considered a reliable sprinkler. Grinnell followed this in 1933 with the Quartzoid bulb. Known as Grinnell C these stayed in the Grinnell product line for many years. These are still available today from Tyco. They are now known as Issue D sprinklers, and only available in temperatures higher that those offered by Job.

Grinnell Quartzoid D 1967

The other companies that I know of that attempted glass bulb sprinklers is “Automatic” Sprinkler, and Reliable. Central had one in the early 80’s but I understand it was imported from Germany. Other companies may have tried but I have no information on them. Only Grinnell has consistently kept them in production over the years. My knowledge here is limited to what I have in my collection.

Automatic B 1972

JOB GmbH was formed in 1971. This company is the manufacturer of nearly all the glass bulbs used in fire sprinklers today. They offer a complete range of bulbs in both standard and quick response.

The only issue I have with the current glass bulb sprinklers is their delicacy. As sprinklers have gotten smaller, and with the introduction of the quick response bulbs, great care must be taken to protect the sprinklers during installation. The days when a fitter put the heads in a bucket to carry around are gone. At my last company you could get fired for not properly protecting the sprinklers until they were installed.

Now to protect these sprinklers they are shipped with orange plastic guards. The bright color should indicate to the installer that it is still in place and needs to be removed. But I have been to many facilities where I found the guard still in place years later.

And though rare, I have seen bulbs where there was no liquid in them. The one pictured below was found in a spare head box. It has a Job bulb in it. I have had field crews show me ones they removed from service. I always wondered it they were installed empty or if it had leaked out over time.

Central No Fluid

But despite their popularity and cost advantages, I don’t think the fusible link sprinklers will be relegated to the junk heap. Being a little more rugged I still see them installed in places where damage is a concern. In storage racks and low areas where head guards are necessary.

6 Responses to Glass Bulb Sprinklers

  • Mike says:

    Thank you very much for posting this article. I am myself a fire sprinkler collector and I enjoyed reading about the history of the glass bulb type heads. I was previously unaware of Central’s glass bulb type from Germany and Reliable’s attemts in the ’70s/80’s.
    I would like to be able to talk to you more about sprinklers, its not easy finding others with the same hobby. Also, you mentioned other possible manufacturers of early glass bulb types. Hodgman apparently had a try with it before going out of business, I have in my collection a 1982 Hodgman sprinkler with a red glass bulb.


  • Editor says:

    Hi, Mike

    Welcome to Fire Safe Life, Sorry about the delay in getting back to you. You know how it is being part of the Fire Protection Industry. I’ve been on the road.

    Be sure to visit our forum, that is the place to discuss everything fire protection. Fire Safe Life Forum

  • Mark says:

    Is there any kind of legislation concerning where these devices may be located relative to the IP protection of electrical equipment that may be effected by the water spray?
    My particular concern is lobby areas in places like supermarkets where I have seen these placed between 2 sets of power operated doors including air conditioning unit.

  • Rudd says:

    Not that I know of. I don’t know of any concerns with protection of anything from the water spray of the sprinkler, to us in the sprinkler industry the opposite is usually the case. If the doors or air conditioning unit are on fire, why worry about the water spray? If there is any concern about the IP protection, then whould not the electrical equipment would have the appropriate NEMA enclousure?

  • Rien says:

    The article about the glass bulb sprinklers is very interesting. I am a sprinkler engineer and collector of sprinkler heads.
    I want to add a few comments to the article. Glass bulbs have the advantage of being unsensible to aging, where a fusible link may be.
    The fusible link sprinkler will indeed remain in business, for instance in the food processing industry. They are much more afraid of glass than metal. I have done some projects in the food industry and we had to use sprinklers with a fusible link.
    I indeed believe there are only one or two manufactures of glass bulbs and they supply the whole industry, so the same bulbs may be found in US, Asian and European sprinklers. Referring to the reaction by Mike, there are indeed some other manufacturers that have used glass bulbs. In Europe G.W. in Danmark, Angus and Saval have since a long time produced sprinklers with glass bulbs. I could send a picture of those if you’re interested.

  • Tony says:

    HIi Everyone,

    It is really good to see that there are popele out there nuts enought to pick something like the sprinklers and the technology itself as a hobby or a life. I work for Tyco in Hungary handling sprinkler related sales and tech support, special hazard fire protection. Your wiritings are very useful, and interesting too, I did not have much time to travel back in time to dig into it so much.

    Good job!


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