Are There Fire Resistant Window Screens?
Much has been written about fire resistant materials for roofs, walls, decks, etc but I was wondering what are the best products for window screens? I’m thinking particularly of the screening material used for a screened-in porch.
A lot of people say “don’t use vinyl for window frames, siding or gutters because it is a petroleum based product and it can melt in a wildfire but most screen material is also some form of plastic. Given that fire prevention specialists say that any point of entry on a building can let flying embers inside and ignite an interior fire, what can you do to best protect large openings in a screened-in porch?
I did find this fiberglass product that claims to be flame resistant but are there better choices? And I know that in a wildfire any type of screening will not survive a direct flame front touching the building but research has shown that the majority of building losses from wildfire is actually due to flying embers (the flame front doesn’t get close enough to actually burn he building).
https://www.security-screens.org/securityscreens/fiberglass-mesh.html
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Replies
rockies 63,
Bronze screen material would be one choice. Of course there may be stainless steel as well, but it could be as costly or more. I know from experience that the bronze screen material will mellow over time to be less bright though it might be a season or two. I works fairly easily. You might buy some "dog proof" fiberglass screen and see how it fairs under flame. Lots easier to work with than bronze.
FWIW, I live in a high fire risk area and local code and guidelines focus more on removing vegetation from immediate proximity to the dwelling and a staged reduction of fuel sources further from the house. Basically nothing within 5', some plantings out to 30', limited trees from 30 to 100' and selective clearing beyond. The forest service has a program to help guide the process.
Embers transported by wind tend to collect in corners of eaves, gutters, inside corners on buildings and if poor screening is present, potentially inside attic spaces. Embers come in sizes that scale with wind speeds. A fire on the front range in past years saw wind speeds up to 100mph and ember sizes up and beyond the size of your hand. Embers this size are practically like flying campfires with lots of heat capacity when coming back to earth. More common are small embers that individually don't pack a lot of burn power, but when collected in a mass in a gutter or the tight corner eave of a dormer window, big trouble.
Standing seam roofs have a critical weak point if the top flashing is not sealed between the ribs. On my house the flashing is folded in such a way that neither hornets or embers can make their way up between. My roofs are unvented as vented roofs have two potential avenues for embers to be sucked into the attic. Code here requires 1/8" inch screening for roof eave vents and further extends this to all air penetrations like HRV, furnaces and dryers.
Windows need to be tempered and the frames of low flame susceptible materials. Screens do not get mentioned. While preventing embers from gathering at your windows might help some in a fire situation, I would tend to focus more on removing all combustibles away from the base of the house and keeping bushes and trees 30' away. I have seen photos of homes that survived with even the minimal 5' rule being applied.
Terrain is another critical factor along with deck construction, but that is another discussion.
Agreed. Vegetation burns the house down.
While advertised as a fire protection, have you ever heard of a house with on fire vegetation that didn't burn down because it was fiber cement cladded? Did it not burn down because of the cladding or because trees and bushes that did burn were not feet away from the house.
My guess is the examples are far and few between with apples-to-apples building material saving the day vs vegetation (fuel) management.
Can you elaborate more on the top flashing folding? I'm not familiar enough with standing seam roof details to visualize it.
andyfrog,
You an see it at the top of this photo of my shed. The ridge cap gets cut around each one so it is tight to the panels.
I wonder if a fire resistant blanket would work to protect large openings (like in a screen porch)?
https://adlinsulflex.com/blog/insulflex-fire-blankets-for-construction-sites/
Of course, you'd have to be home if a wildfire was reported nearby, and you'd have to have a hanging system in place on the exterior of the house in order to secure the blanket in place but it might offer a lot of extra protection from embers.
There's also this article on whole house fire blankets.
https://www.frontiersin.org/articles/10.3389/fmech.2019.00060/full
Any other options?
rockies 63,
There are roll up metal shutters that can be dropped down over windows and other openings, but they do exact a heavy toll on aesthetics. Alternatively, there are a few companies selling a sprayed on coating for structures and vehicles that they apply just ahead of the fire reaching your location. Not the best approach perhaps given the need for good timing and their availability.
Self applied kits are available if you have both a high volume sprayer and a large amount of water. I recall it would run 4-500 dollars for a kit. Not clear on coverage. The sprayed product is much like the gel in diapers. The water swells it up on the way through the sprayer and it sticks to your house or car. I saw a demo video that protected a trucks door and windows from a very scary blow torch thing. The paint did not even bubble.
As I live in a high risk area, code allows for placement of a 10,000 gallon tank on one's property for the fire trucks to tap. Fittings of course set to the fire department standards. Of course that would suggest the fire department has time to come to your house when likely they have much bigger problems on hand.
Best answer for fire hardening a home is to design out the ember catch points, keep vegetation at least 20' away from the house. Reduce the available fuel out 100' if you have that much acreage. Keep a bug out bag and aim your propane tank away from the house or bury it.