Friday, May 6, 2016

Dry Heads

Example of a dry head, installed in ordinary combustible attic, fed from CPVC piping.  Note, NFPA 25 excludes confined, concealed and attic places from visual inspections.

The glass bulb (GB) standard spray upright dry head photographed below failed (leaked).  Attempted removal of the dry head assembly resulted in unintentional destruction of the CPVC head adapter as result of torque overload.

Photo below shows a disassembled horizontal sidewall dry head.  Incorrect removal (by the defelctor side) resulted in unintentional destruction of dry fire sprinkler:

A close-up:

A manufacturing defeat is shown below.  By standard and listing the color blue in the assembly's glass bulb indicates this head will operate at 286 degrees F.  The deflector, however, is marked 155 Degrees. When this was discovered the manufacturer was notified. 2003 SIN TY3255 QR SSP-12.

And now for photograph of the deflector:

The next head was removed from service:

And another leaking dry SSU:

Below, a typical install [happens to be a famous 100+ year old hotel], dry head is indicated with arrow.

Last photo shows two dry heads, one head is in the correct orientation, the other is not.

The following photo shows in situ 200 degree dry head pendent installed to protect cold storage [food].  From the top of the freezer box the dry head is shown:

The photo below shows a  small amount of ice on the deflector of a dry fire sprinkler head.  Subsequent investigation did not show an ice plug.  Ice is likely a result of condensation.

Another photo of the same dry head:

The following photo shows a mechanically damaged dry head (ME-1) found in client inventory:

No comments:

Post a Comment