# Duct Detectors



## fireguy (Jan 3, 2015)

As promised, duct detectors.  72-2013 Table 14.4.3.2 (5) & (8) Page 260

We can use a whole can of smoke, and still not get a duct detector to trip while the air is moving.  W/O air movement, we can usually get the duct detector to trip.  We have removed the tube and cleaned the sponge rubber filter and that does not make any difference.

Any thoughts?


----------



## cda (Jan 3, 2015)

Test per manufacture recommendations


----------



## cda (Jan 3, 2015)

http://www.firealarm.org/duct_det_test.pdf

system sensor's procedures:::

http://www.systemsensor.com/en-us/Documents/D4120_Manual_I56-2967.pdf


----------



## fireguy (Jan 4, 2015)

Thanks, we have a job coming up this month that has duct detectors that we have had problems with.


----------



## cda (Jan 4, 2015)

""""have removed the tube and cleaned the sponge rubber filter and that does not make any difference. """"

What filter???

All tubing should be open

One completely and one with a plug but holes drilled in the tubing or now there is a partial opening the length of the tube

Forgot fireguy are you on the private side , system installs??


----------



## fireguy (Jan 4, 2015)

On the contractor side. All alarm work is subbed out, but I am normally on site during inspections.

The sample tubes I have seen that were removed had a sponge rubber filter in the tube.  The filter is in the end of the tube that goes into the smoke detector.   You would be surprised at the amount of dust and dirt in the sponge rubber.


----------



## cda (Jan 4, 2015)

Would pull up the manufacture's installation sheet and check all aspects

I do not think I have seen one with a filter on the sampling tube


----------



## cda (Jan 4, 2015)

fireguy said:
			
		

> On the contractor side. All alarm work is subbed out, but I am normally on site during inspections.  The sample tubes I have seen that were removed had a sponge rubber filter in the tube.  The filter is in the end of the tube that goes into the smoke detector.   You would be surprised at the amount of dust and dirt in the sponge rubber.


Require fire alarm company to supply equipment and test per manufacture


----------



## cda (Jan 4, 2015)

cda said:
			
		

> Require fire alarm company to supply equipment and test per manufacture


Sorry I sometimes only think in my small squirrel cage.

We have an amendment that duct detectors be powered and reset from the fire alarm.

In the real world I know a fire alarm company might install the duct detectors or may only monitor what has been installed by a/c manufacture or mechanical contractor, which can cause problems at times.

No matter what still need to be tested her manufacture.


----------

