Thursday, August 24, 2023

Fire Hazard Prohibition of Cheap Fans, Can Lights or Cut-In LED Edge Lights

The just-prior post at this blog is a  call that all residence attic access portals must be suitably air-tight and resistant to fire propagation. By the same reasoning, ban ceiling lights that penetrate drywall, leaking energy and propagating fire. Where the USA has surrendered leadership in lighting concepts to myriad fabricators in China, clip-in LED edge lights have become a madness tipping point. These clip-in lights dominate big-box store displays, ruining homes with ceiling cuts nearly as big as the light lens diameter.

Many posts at this blog deal with air-tight disk-LED installation in strong RACO 175 steel boxes. There is much reporting of the fire-resistant and efficient replacement of awful can lights, with box-mounted disk LEDs. With factory-produced drywall rings precut to can OD and RACO 175 octagon ID, and with some patching grout, a can light may be upgraded in an affordable few minutes. Of many jobs with lighting improvement, one of Winter 2014 is most memorable, for thorough presentation of the math of energy savings. This home built in 1988 was the subject of four blog posts already:

Math Of Under-R12 Attic Floor Insulation Rule, For IncentivesMarch 17,2014.

I was called to improve personal safety and the capacity for attic storage. I added fire safety at the attic access, but was not yet mindful of other ceiling penetrations as matters of safety against fire propagation.

A silly hinged wood door opening to dangerously small headroom, gave little storage potential nearby, over tops of 2x4 truss bottom elements, among loose-fill fiberglass insulation. Something smarter was wanted.

At planned egress to the attic under the roof peak, see that there is no fire separation of garage and house attics. An attic ladder to be added, must be thirty minutes fire-rated, matching surrounding 1/2" drywall. Yes, this garage ceiling has 1/2" drywall. 

I offered this new "Calvert Recovery" Size 2248 fire-rated attic ladder, set in 2x4 trusses strengthened as better than 2x10 framing. Good Calvert USA ladders with small premium for fire rating, were a fleeting opportunity in 2014. The Maryland attic ladder business operated for about ten years, beginning with a few wood attic ladder models built in the Czech Republic. Ladders then Made In USA had novel features including frames and steps built of best 3/4" plywood, stiffer and stronger than ordinary wood.  The factory closed in 2016.

The Calvert fire-resistant door is of heavy 3/4" thickness treated-composite wood. Not rated, but at least U = 0.25, with affordable heat loss when properly gasketed.

Here the installation is fire-sealed about the ladder frame, with a strong taper of flexible grout covering reveal of the wood ladder frame. I do not use wood trim, that usually just hides shimmed large clearances about the frame, defying the fire rating.

With the better access,  replace a badly-installed-as-usual noise-maker bath fan.

Does this look like much of a fire barrier to you?

Plastic bodies, thin aluminum frames and large flame paths at air gaps are fire-propagation hazards.

Don't expect to find an offered fire-rated bath fan.

The aluminum flex duct too, will incinerate quickly, although slower than a silly plastic duct.

We find duct foolishness like this even with a kitchen exhaust fan sometimes, Here it is not a building code violation. A much shorter duct directed through-roof,  is just common sense, and is required by rebates sponsor Energy Trust of Oregon.

I offer only simple and rugged Panasonic bath fans as replacements. The solid steel body with penetration only at the duct bell, might sport a 30-minute fire rating if required. It clearly is improvement. The hard-plastic grill is not an accelerant of flame.

Preset the outlet bell assembly standing alone, clipped to drywall.

Insert the body from below, sliding past and securely attaching to the outlet bell assembly

There will be no fire propagation about the fan body.

Wall header gaps commonly 1/8" surely propagate fire that has penetrated walls. Learn to see sealing of gaps as mandated by fire-prevention codes.

My flexible grout, chemically similar to Custom floor tile grout, will not carry flame. 

Foam foolishly prescribed for weatherization contractors, is immediately skinning, and rarely bonds airtight. The foam itself is quite flammable. Foam sealing must be forbidden. I remove and replace foam whenever found. What a mess. What a crime.

Two incandescent bulbs upon porcelain lamp-holders supplemented the twist CFL bulb of the garage door opener, in a dismal garage. The 2 7/8" fiberglass box with knockouts, and large gaps to drywall, both propagate flame.

There is no economy in junior box size; crammed wiring is less safe. A best LED light now demanding converter space in the box, is not possible.

Install air-tight RACO 175 boxes with mount structures built of scrap 3/4" plywood and select 2x4 remnants.

Lithonia Versilite FMML 7 830, two places. 

Note to self nine years later: I must fully grout the RACO 175 to drywall annulus despite nearly airtight enclosure when the luminaire is pulled against the ceiling. Keys for mounting screws admit bugs seeing light through the box annulus.

Lighting in the garage remains barely adequate. In a wished  return visit look for bugs in light lenses, and offer more light positions.

I have no room-side photo record of six can lights found  in the kitchen, holding hot 150 watt incandescent floods by my records. 6 1/4" OD cans had especially large annular gaps, to 7" drywall cuts. Can interiors must have been loaded with cobwebs.

Lightolier cans over the kitchen have the usual obstacles to absurd covering of a non-IC can with a Tenmat Hat, never air tight to the drywall, little resistant to fire, not resisting energy losses, certain to be thrown off by pressure differential in a fire.

Poorly-accessible space over the kitchen sink was warmed with lack of insulation, congenial to mud wasps.

The better kitchen ceiling has the 7" opening of a can invisibly and quickly replaced by a ring of GP Densarmor drywall, fitted to a heavy-gage steel RACO 175 deep junction box. There are no leakage paths from the box, to the attic. This is fire-proofing!

The drywall ring has full penetration grouting at the OD and at the RACO interface. I have built and installed hundreds of these mount structures built of scrap 3/4" plywood and select 2x4 remnants. Two screws attached through the ceiling drywall pull the patch into alignment.

6" Glimpse LED disks are not glaring. They are pretty.

A bit of fire-proofing, however much perpetual energy saving was the sure achievement. Those savings are detailed in the linked prior blog posts for this home. Copy the math statements here:

The can annulus diametral clearance was 7” - 6.25 = 0.75”, quite large. The frame was not pushed against the ceiling, and probably did not further constrict the passage of leaking air. Each can light had a gap of up to 7.8 sq in.  Apply Insulation Math for a Portland, Oregon home with a common 88%-efficiency furnaceThe annual cost of heating lost air is $0.555*Path Area, $4.30 per year. At four places I replaced a 65 watt incandescent downlight with a 750 lumens 14.5 watt LED. Another can that had a long-dead 65 watt incandescent was patched out. At the sixth can, over-sink, I installed a 450 lumens 9.5 watt LED in place of a 150 watt incandescent downlight. 

Apply Insulation Math . Completing insulation in the floor should save, at each light:
$2.4 * Baffled Area, sf* (1/3 - 1/50)  = $0.75 * Baffled Area, sf
= $1.30 per year for an 18” baffled circle (1.8 sf).
= $3 per year for 4 sf uninsulated over the kitchen sink

There is about $6 per year typical savings from air sealing and insulating each very leaky non-IC can light. 

Additionally, credit $12 per year electricity savings vs. the found 150 watt incandescent flood bulbs, with basis $0.11 per KWH. 

Overall annual savings for the home due to my work:
$116 (22%) Fix Kitchen Lights
$160 (30%) Insulate Attic Walls to R30
$101 (19%) Seal Wall Headers
$199 (29%) Insulate Attic Floor to R38

$536 total annual energy savings

 A small flight of steps beyond the ladder egress serves much of the added storage area, little obstructed by truss uprights.

.Treasure was was waiting to be found in the efficiency, safety and usefulness of an attic.

Added content 9/3/2023:
With the encouragement of a received comment, add details in this job, of the bath fan replacement, that is is fire-resistant as can be. I replace awful plastic noise-makers with solid-steel-boxed basic Panasonic fans. See posts Label Bath Fans., steel-ducted through the roof just as is code-required for kitchen exhaust fans with their grease-fire propensity.