Can a Vacuum Cleaner Really Clean a Smoke Detector

 Can a Vacuum Cleaner Really Clean a Smoke Detector?

Being a Fire safety expert, technician, engineers ask to use a can of air or blower or vacuum cleaner to clean smoke detectors. What do you think?

Compressed Air is not Allowed

The manufacturers that I know about have a policy that their warranty is voided if compressed air is blown into the smoke detector. Once a smoke detector has compressed air blown into it, they won't stand behind their product because of potential damage caused by the high velocity air.

Because the process of "listing" a device is started by the manufacturer, I suppose that also means that the smoke detector, no longer backed by the manufacturer's warranty, is no longer "listed" as a smoke detector. Remember, the NFPA says that all devices used in a fire alarm system have to be listed for Use in a Fire Alarm System.

Don't use compressed air (a can of air is compressed air).

Sticky Dust Particles

Most of the time, to make the smoke detectors dirty, dust particles are sticking to the inside of a black photo chamber; the dust particles are "sticky". The particles that aren't sticky will mostly just bounce off the black plastic of the chamber side and usually pass on out of the chamber.

You've seen the dust that sometimes accumulates around air vents? That is an accumulation of sticky dust from the air. That's the same sticky type of dust particle that is sticking to the inside of the photo chamber of a smoke detector.

My wife claims that the only way to clean that kind of dust is with a soapy solvent, and a cleaning rag. Because of the solvent, using those tools to clean a smoke detector will damage it, so don't use any water or chemical inside a smoke detector.

A clean, dry, fine cloth can be used to dislodge a lot of the sticking dust particles, but to loosen up the particles in the crevasses of the chamber is difficult to impossible. Besides, to use a cloth, you will have to open-up the smoke detector.

Check with technical support for the detector's manufacturer to find out if opening the detector will void the warranty. Sometimes the manufacturer will sell replacement photo chambers. That's one possible solution.

Vacuum Cleaner

A vacuum cleaner uses low velocity air to pull the dust particles away from the sides of the photo chamber. If the particles aren't sticking very strongly to the sides of the chamber, a vacuum cleaner will remove them. However, because the air stream is disrupted by the light baffles around the chamber, and the insect screen around that, the velocity of the air is very slow and won't dislodge the really sticky dust particles.

A vacuum cleaner really doesn't clean a smoke detector.

Dust the outside of the smoke detector with a dry microfiber cloth. Remove the battery and plan to dispose of it safely. Use a paint brush or your vacuum's upholstery tool to clean the interior and the air vents of the unit. Be gentle in order to avoid causing damage to the circuit board.

Some Engineer allow to open detector all fittings and use blower or vacuum cleaner to remove dust from circuit board or light sensor.

Compressed Air or vacuum cleaner is not recommended to clean Smoke detector, Heat detector.

NFPA Cleaning

The National Fire Protection Association (NFPA) does talk about regular cleaning of smoke detectors. However, the NFPA doesn't provide a procedure to clean the detectors. They leave that up to the individual manufacturers.

Often, the manufacturers will be able to provide an inexpensive attachment for a vacuum cleaner. However, because it is non-invasive to the smoke detector, it will still not dislodge any sticky dust particles. Those sticky dust particles are what make most actually dirty smoke detectors stay dirty even after using a vacuum cleaner.

Always take suggestions from certified fire expert or manufacturer technical person via email communication.

Some Expert suggest once panel shown detector is dirty, just replace with new one.

Fact for you:

The fact is that all smoke detectors need to be replaced when they reach 10 years of age, and in many instances, smoke detectors can fail or become problematic well before this time.

Please feel free to ask any questions you may not be sure of, but I’d also enjoy hearing what you liked about the article. 

It’s over to you now …

Further reading:

http://bhadrafiresafety.blogspot.com/2021/07/smoke-detector-testing.html

http://bhadrafiresafety.blogspot.com/2021/05/heat-detector-testing.html

http://bhadrafiresafety.blogspot.com/2021/08/flame-detector-testing.html

http://bhadrafiresafety.blogspot.com/2021/10/maintenance-of-smoke-heat-detector.html

Fire Alarm Evacuation with Low Frequency Sounder

Fire Alarm Evacuation with Low Frequency Sounder

Is your jurisdiction enforcing the new code mandated 520 Hz low frequency sounders for fire alarm audibility yet?  If so how are you tackling this new requirement?  And finally did you know that the smoke alarms within the sleeping rooms and guest units do not need to meet the 520 Hz requirement?

When did this start?

Not a lot of people are aware that this requirement was originally noted in the (2010) NFPA 72 National Fire Alarm Code section 18.4.5.3.  It states "Effective January 1, 2014, where audible appliances are provided to produce signals for sleeping areas, they shall produce a low frequency alarm signal that complies with the following:

(1) The alarm signal shall be square wave or provide equivalent awakening ability.

(2) The wave shall have a fundamental frequency of 520 Hz +/- 10 percent.

Now we fast forward to 2019.

Note that the (2019) NFPA 72 Fire Alarm and Signaling Code requirements are the same found in Section 18.4.5.3

Now let’s break it down.  There are a lot of code sections so stay with me.

The Annex A of NFPA 72 (2019) section A18.4.5.3 lets us know that this section does not cover the audible requirements of single and multiple station smoke alarms and instructs us to consult chapter 29 for said requirements.

If you refer to Chapter 29 "Single and Multiple-Station Alarms and Household Fire Alarm Systems" section 29.3.6 it states the following: "All audible fire alarm signals installed shall meet the performance requirements of 18.4.3, 18.4.5.1, 18.4.5.2 and 29.3.8."  Please notice that this section does not include section 18.4.5.3. This may lead one to believe that single and multiple station smoke alarms for dwelling units do not need to meet the new 520 Hz low frequency requirements.

The key section to pay attention to here is section 29.3.8 which states "Notification appliances provided in sleeping rooms and guest rooms for those with hearing loss shall comply with 29.3.8.1 and 29.3.8.2, as applicable."

Section 29.3.8.1 "Mild to Severe Hearing Loss.  Notification appliances provided for those with mild to severe hearing loss shall comply with the following:

(1) An audible notification appliance producing a low frequency alarm signal shall be installed in the following situations:

    (a) Where required by governing laws, codes, or standards for people with hearing loss.

    (b) Where provided voluntarily for those with hearing loss.

(2) The low frequency alarm signal output shall comply with the following:

    (a) The waveform shall have a fundamental frequency of 520 Hz +/- 10 percent.

   (b) The minimum sound level at the pillow shall be 75 dba, or 15 dba above the average ambient sound level or 5 dba above the maximum sound level having a duration of at least 60 seconds, whichever is greater."

Section 29.3.8.2 "Moderately Severe to profound Hearing Loss.  Visible notification appliances in accordance with the requirements of 18.5.5.7 and tactile notification appliances in accordance with the requirements of section 18.10 shall be required for those with moderately severe to profound hearing loss in the following situations:

(1) Where required by governing laws, codes, or standards for people with hearing loss.

(2) Where provided voluntarily for those with hearing loss.

What does this mean?

The SpectrAlert Advance HR-LF by SystemSensor

If we read section 29.3.8 very carefully you will notice the word "AND" between sleeping rooms and guest rooms for those with hearing loss.  This is telling us that the requirements of section 29.3.8.1 and 29.3.8.2 apply to ALL sleeping rooms including guest rooms for those hard of hearing.

How does this effect your design ?

To this date there are no UL listed UBC smoke alarms that can produce an audible tone at 520 Hz.  In fact the only manufacture that has a UL listed 520 Hz low frequency sounder appliance is System Sensor.  This means no more mini horns in the sleeping rooms of R-1, R-2 and R-2.1 occupancies.  The only way to accomplish this is by installing a System Sensor HW-LF (low frequency sounder) or addressable smoke detector with low frequency sounder base in place of all mini horns.  This will give us the required 520 Hz in all sleeping areas during a general alarm condition.

The SpectrAlert Advance P2WH-LF by SystemSensor

How do we accomplish 520 Hz when the Single or multiple station smoke alarm is activated?

Since there is no such thing as a low frequency LISTED smoke alarm, I propose installing addressable system smoke detectors in all sleeping rooms and guest rooms.  On top of this an addressable control module will need to be installed for each residential unit.  The control module will then need to be wired so that it controls an individual NAC (Notification Appliance Circuit) for that particular unit.  Through programming we can activate this individual control module upon activation of any smoke detectors within the unit.  Lastly the control module for each unit will need to be mapped to activate during a general alarm condition.  This way we are activating the in room low frequency sounders via the in room smoke detectors as well as any building wide general alarm device.  This method allows us to accomplish the requirements of section 18.4.5.3 as well as 29.3.8 with listed equipment and methods.

Are any facilities exempt from this requirement?

Healthcare settings, correctional/detention facilities, and other facilities where private mode signaling is employed and where staff are trained to alert and evacuate occupants according to established protocols are exempt from the low frequency sounder requirements. In addition, these requirements do not apply to dwelling unit life safety systems as single- and multiple-station alarms and household fire alarm systems have requirements outlined in Chapter 29 of NFPA 72. You should always check with your AHJ for local requirements for your facility.

How does this effect your final cost?

Obviously there is a lot more equipment needed to perform this requirement such as addressable system smokes and control modules.  On top of this the low frequency sounders are more expensive than mini horns.  Also note that the new low frequency sounders draw more current than mini horns which will decrease your total allowable appliances per NAC ultimately increasing the number of required remote power supplies.

This is going to be a huge adjustment for our industry which will ultimately comes with a large learning curve.  I suggest your contact your local AHJ (Authority Having Jurisdiction) and find out what their interpretations on this subject are.

Building operators should consult with their local fire marshals to determine the status of the regulation's adoption and enforcement in their area to assess their timeframe for installation. The next conversation should be with dealers to discuss available options that best fit the building's needs. The ease or difficulty with which the new requirements are deployed will come down to the system and the manufacturer. Low frequency devices that can be easily retrofitted into existing installations are a quick, cost-effective solution for meeting new code requirements. However, it is also important to understand that power supplies, audio source units, amplifiers, sounders, sounder bases, and speakers all play a part in achieving code-compliant 520 Hz signaling. Special design consideration may be required to accommodate low frequency notification in current life safety systems.

Resources:

http://www.nfpa.org/codes-and-standards/document-information-pages?mode=code&code=72

http://www.facilitiesnet.com/firesafety/article/NFPA-72s-Low-Frequency-Sounders-Requirement-Takes-Effect–14764

https://www.foxvalleyfire.com/contact.html

How Optical Smoke Alarms Work

How Optical Smoke Alarms Work

An optical smoke alarm (also called photo-electric smoke alarm) works using the light scatter principle. The alarm contains a pulsed Infra red LED which pulses a beam of light into the sensor chamber every 10 seconds to check for smoke particles.

When a fire breaks out smoke will enter the optical chamber through the opening vents. Smoke alarms from quality manufacturers have the chamber protected with insect screens to stop bugs entering and causing false alarms.

As the smoke enters the optical chamber, its particles cause the Infra red light to be scattered onto the photodiode light receptor.

Once the scattered light hits the photodiode light receptor a signal is sent to the integrated circuit which causes the alarm to sound alerting the occupants to the fire.