Residential smoke alarms.
- Thread starter ARF
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renosteinke
Senior Member
- Location
- NE Arkansas
You don't ask for much, do you?
Smoke alarms that are hardwired, with battery back-up, are required by the UL standard to be able to pass the smoke tests after running on batteries alone for a week. Horn, strobe, communication- that's a lot of load for a little battery. The usual requirement for the horn is for it to be 85db loud. Hearing impaired? Probably 105db- that 100x as loud. More noise = more power.
At some point you just have to admit defeat and put in a REAL alarm system.
Smoke alarms that are hardwired, with battery back-up, are required by the UL standard to be able to pass the smoke tests after running on batteries alone for a week. Horn, strobe, communication- that's a lot of load for a little battery. The usual requirement for the horn is for it to be 85db loud. Hearing impaired? Probably 105db- that 100x as loud. More noise = more power.
At some point you just have to admit defeat and put in a REAL alarm system.
dhalleron
Senior Member
- Location
- Louisville, KY
To my knowledge none of the smoke alarms on the market battery back up the strobe light.
Also National Fire Alarm Code does not require the strobe to be battery backed up. This is from 2011 NFPA 72 pertaining to single station smoke alarms and household fire alarm systems:
29.6.5 Notification Appliance (with Smoke or Heat Alarm). If
a visible notification appliance is used in conjunction with a
smoke or heat alarm application for compliance with 29.3.7,
the notification appliance shall not be required to be supplied
with a secondary power source.
Also National Fire Alarm Code does not require the strobe to be battery backed up. This is from 2011 NFPA 72 pertaining to single station smoke alarms and household fire alarm systems:
29.6.5 Notification Appliance (with Smoke or Heat Alarm). If
a visible notification appliance is used in conjunction with a
smoke or heat alarm application for compliance with 29.3.7,
the notification appliance shall not be required to be supplied
with a secondary power source.
renosteinke
Senior Member
- Location
- NE Arkansas
That's very nice, but I don't think NFPA 72 is relevant to smoke alarms - that is, the residential gizmos, not the detectors that are part of a central alarm system.
It's been quite some time since I read the appropriate UL standard, but it would be my guess that a residential smoke alarm would be required to operate all signalling components under alarm conditions, even after a week on battery-only power.
Bear in mind that the one-week requirement is for the residential units; proper alarm systems only have a 90-minute battery back-up requirement.
It's been quite some time since I read the appropriate UL standard, but it would be my guess that a residential smoke alarm would be required to operate all signalling components under alarm conditions, even after a week on battery-only power.
Bear in mind that the one-week requirement is for the residential units; proper alarm systems only have a 90-minute battery back-up requirement.
Chapter 29 of NFPA 72 is relevant and does cover residential "off the shelf" stand alone smoke alarms as well as whole house systems.
Roger
IMO A fire system for a hearing impaired person should be an engineered monitored system, with a control panel and monitoring, with an engineered system all the device loads be accounted for to provide the needed battery back up, another tip,make sure your insurance covers alarm liability with E & O and liability contract clauses for limited liability.
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