In May, I discussed questions often raised by those in the field trying to understand the requirements that affect their fire alarm system installations. This article follows the same format.

How do I use 177 candela (cd) visible notification appliances on a 24V DC fire alarm system when 177 cd appliances require 120V AC? How would one monitor the integrity of the circuit connected to this appliance?

First of all, you need to contact the manufacturer of the fire alarm system control unit you intend to use to determine how that manufacturer recommends that you connect 177 cd visible notification appliances to the unit. The installation manual for the fire alarm system control unit may already have this information. Very few people realize that the nationally recognized testing laboratories review the contents of the installation manual for a particular piece of fire alarm equipment and include that manual in the listing for the piece of equipment.

Of course, the only instance where you would normally use 177 cd visible notification appliances would include sleeping areas where the distance from the ceiling to the top of the lens of a wall-mounted visible notification appliance is less than 24 inches. This distance describes the anticipated depth of a smoke layer during the initial stages of a fire within the sleeping room. Listed 177 cd visible notification appliances that operate on 120V AC include a means within the appliance to monitor the availability of the power and operate a set of contacts should the power fail. NFPA 72-2022, National Fire Alarm and Signaling Code, makes provision for operating interfaced equipment in Chapter 21. This chapter includes a requirement to monitor the integrity of the interconnecting means. An installation contractor could use a fire alarm output from the fire alarm system control unit to connect to the 120V AC powered 177 cd visible notification appliance. This same circuit could monitor the contacts of the appliance that indicate the loss of AC power.

We are updating some of our training materials and have an internal debate going about the application of the spacing in Section 17.6.3.1.1 and the irregular spacing areas rules in 17.6.3.1.2 as it relates to Section 17.6.3.5.1, which requires that “Unless otherwise modified by 17.6.3.5.2, on ceilings 10 feet to 30 feet (3.0 m to 9.1 m) high, heat detector spacing shall be reduced in accordance with Table 17.6.3.5.1 prior to any additional reductions for beams, joists, or slope, where applicable.” We have always understood or believed that a room with a 12-foot ceiling, for example, would require that the listed spacing for the device be reduced by multiplying the listed spacing by 0.91 and that the same reduction would apply for determining the distance to walls and partitions measured at right angles or for measurement of irregular areas that this reduction also applies. So, a device with a listing of 30 feet would now be a value of 27.3 feet when applying the rule and multiplying this reduced dimension by 0.7. Are we interpreting this correctly?

You are correct with your example as stated. You would always reduce the listed spacing in accordance with Table 17.6.3.5.1 first and then apply any other reductions required in other sections related to ceiling configuration. Just remember that the table only applies to heat detectors and does not apply to smoke detectors or to line-type heat detectors.

It’s been a repeating battle with salespeople where they sell something and insist we move forward with what they sold, only to be told by an AHJ that something else needs to be done and we look dumb in front of the owner. System replacements are one of them. What I’m hoping you can show me is where it states that a panel replacement does or doesn’t require that you now bring the whole protected premises up to code. My understanding was if it was a defective fire alarm control panel (just not working for any number of reasons) that a panel- for-panel replacement was allowed without any other code updates required. But if the panel is just being upgraded, when does the whole system need to follow suit?

I am pretty sure there is no exact code requirement that answers your question. In my opinion, when the fire alarm control unit (FACU) is replaced, the system will need to be upgraded when it is not compatible with the existing devices, or the new devices you might be installing will potentially require a new FACU. Or if the FACU is obsolete and is replaced, then it’s a good chance the system will need a total upgrade.

That said here is what my research turned up:

• NFPA 1, 13.7.1.5.7: The system owner shall replace required fire alarm systems that cannot be serviced or repaired to eliminate system impairments or chronic nuisance alarms [AHJ opinion].
  
• NFPA 101, 29.3.4.3.6: Where the existing fire alarm system does not provide for automatic emergency forces notification in accordance with 9.6.4, provisions shall be made for the immediate notification of the public fire department by telephone or other means in case of fire, and, where there is no public fire department, notification shall be made to the private fire brigade.
• NFPA 101, 29.3.4.3.7: Where a new fire alarm system is installed or the existing fire alarm system is replaced, emergency forces notification shall be provided in accordance with 9.6.4.
  
• International Fire Code (IFC-2018), 907.5.2.3 Visible alarms: Visible alarm notification appliances shall be provided in accordance with Sections 907.5.2.3.1 through 907.5.2.3.3. Exceptions: 1. Visible alarm notification appliances are not required in alterations, except where an existing fire alarm system is upgraded or replaced, or a new fire alarm system is installed.
  

Nothing in the above requires the FACU replacement when you replace or add smoke detectors to an existing system. However, if the AHJ has experienced a large number of false alarms from the facility, they may require a new FACU when the smoke detectors are replaced.

As stated above, the FACU replacement may generate a whole system upgrade, especially if the new one is not compatible with the existing smoke detectors. Ultimately it may be an AHJ call, but you are responsible for checking with the AHJ before you attempt to install what the salesperson sold. 

I would also recommend that when you are bidding on a device replacement you look at the FACU, call the manufacturer and find out how long the FACU will be supported with replacement parts. Then it may be your responsibility to advise the owner before the AHJ steps in and requires it.