Spare Head Box
Here are a few things to know...

When are they required to be installed?

  • on every project!

Where should it be installed?

  • typically speaking we install these on the wall near the riser.


  • Yes...but there are exceptions.
  • Code says the cabinet should be "..maintained on the Premises." which really means it could be kept up with somewhere on site.  
  • The building owner or manager might prefer the box to be installed elsewhere so check with them before installing if applicable.
In a large plant or campus the plant maintenance manager or director may want to keep the spare head box in his maintenance shop for safekeeping.  This is allowed by code as long as it is readily accessible.


So, what really is supposed to go in the box?

Here is what code says...
  1. sprinklers
  2. wrenches
  3. list of sprinklers installed
That's it!  Pretty Simple.

How many sprinklers?

It depends on how many sprinklers are installed in the "facility".
​Look at this table...

Let's look at a few examples.

You are installing a single system and it has a total of 250, 1/2" brass uprights. In that case you would only need 6 spare sprinklers in the box.

Let's say you install 30 more sprinklers on the same job but they are pendents for an office area.  You are still under 300 so you only need 6 total, but now you have 2 head types.  You would install 2 pendents and 4 uprights in the box.  Remember, you have to have a minimum of 2 heads per head type in the box!  

Lets say you install only 10 sprinklers in an existing system and the sprinklers we install are not the same type as the existing.  Add 2 of the newly installed sprinklers to the existing head box.  If there is no head box then install a new box and put your new heads in it and attempt to fill the box with heads that would match the existing style, temp, thread,etc.  We want to leave the customer with the appropriate spare stock.

Lets say you have a building with 4 sprinkler systems, with 3 different head types and a total of 1250 sprinklers.  We know from the Table, that we have to have a minimum of 24 sprinklers since we are over 1000.  We also know that we have to have a minimum of 2 sprinklers per head type.   
In this case, I would divide up the required stock of 24 sprinklers based on the quantities of the various head types. For example you might only have 10 sprinklers of one head type on a dock, 140 sprinklers of another type in the offices and 1100 sprinklers in a warehouse.  I would place 2 spare dock sprinklers, 4 spare office sprinklers  and 18 spare warehouse sprinklers in the head box(s).  

What about wrenches?

NFPA 13 code says to place 1 wrench per each TYPE of sprinkler installed.

If one wrench will fit more than one head type then that one 1 is sufficient.

If you have a socket style wrench go ahead and leave a ratchet in the box with it as well.  Go the extra mile!

Anything Else?

  • Dry pendent sprinklers are not required to have a spare stock, if they are of different lengths...which is almost always the case.

  • Be aware of the maximum air temperature where you install the spare stock.  You won't want to leave a stock of 135 degree sprinklers in a space where the temperature is going to exceed 100 degrees.  A rule-of-thumb to use is the temperature of the room should max out at about 60 degrees below the temperature rating of the head.  So for a 155 degree head you really dont want the heads to be exposed to more than 95 degrees.

  • Don't forget to install our "Service Sticker". This is very important!  Make it look good, your reputation is on the line.​​​


Come home to your family today in one piece!