- [Speaker] Things are moving quicker than they ever have before.

- [Speaker] In our culture, we accept fires.

- As the number of people dying per fire didn't change over 40 years, why didn't that set off red lights?

- [Homeowner] Do we need a fireproof home?

- You know, it's not the way I would go about doing a remodel, but it's it's an upside.

- [Narrator] "Home Diagnosis" is made possible by support from Broan NuTone.

Better air, better life.

By the Got Mold?

test kit.

Real science, real simple.

By AirCycler, Retrotec, Rockwool, and RenewAire.

By generous support from these underwriters, and by viewers like you.

(bell chimes) - [Announcer] Please standby for further instructions.

- 21 flights of stairs.

(intercom chimes) - [Announcer] The fire trucks have arrived.

Please standby for further instructions.

- [Producer] You might as well just go down- - Yeah, let's just keep going, 'cause you can't open these doors.

(intercom chiming) We gotta go down to the bottom door, anyway.

- That is one way to be woken up at 3:30 in the morning.

- But we have our big camera, we have all of our footage.

So, worst case scenario.

- It was a false alarm.

This happened three nights ago, apparently.

Accidents happen.

(somber music) - [Narrator] It's the shields we build.

And the risks we take.

It's the disasters that will test us, and what will grow from them.

It's real life.

And the physics, chemistry, and microbiology of the science of homes.

(somber music continues) - Welcome back to "Home Diagnosis."

- Over the past two seasons, we've learned so much about the latest indoor physics, chemistry, and microbiology research that our brains exploded.

- And at the same time, the number of extreme weather and pollution events has also exploded, reaching right inside our homes.

- So, let's examine the science of homes from the lens of disasters, on this show that's always been a little bit different.

- Everybody watches these TV shows where, let's face it, to have a good TV fire, you have to show the firemen crawling through the room, and maybe two or three pieces of furniture on fire, and they put the fire out, or they save the baby.

That's not the way it works.

When you wake up, the house is filled with smoke.

When you have smoke, particularly from synthetic materials, it's irritating to your eyes.

So the key point in the fire, obviously, it's important when you die, but the really key point that we have to change, or affect is when you're trapped, when you stop moving.

If you stop moving, you will eventually die, unless the firefighter comes to rescue you.

They did these scenario studies that say, let's look at the way people are dying in fires, and see where the smoke detectors can help.

According to the US Fire Administration, and the NFDA, both collect statistics on this, about 40% of the people who die in fires die with a working smoke detector.

It was documented by the chief to have operated.

About 40% die when it's not there at all, and 20% die when it's been disabled.

When I ask people to guess how many people die with a working smoke detector, they always guess something like five or 10%.

I think they'd be shocked to find out that it's 40%.

That number, according to the US Fire Administration, like in the late '80s, was around 20%.

And I think sometimes that's a case of the detector operating, but operating too late.

Think about this, from the time they started collecting it in say 1980 to today, fires are down by half, and fire deaths are down by half, approximately.

But actually, the death per 100 fires is higher now than it was before.

So you're telling me that from a time when only like, say 20% of the country had smoke detectors to a time when 90% of the country has smoke detectors, the number of people dying per 100 fires hasn't changed?

That makes no sense, unless something's wrong.

As the number of people dying per fire didn't change over 40 years, why didn't that set off red lights, and sirens, and say, stop everything?

Let's reconsider everything we're doing.

What are we doing wrong?

- So Shawn, we're in your home.

- Yep.

- That suffered quite the fire.

- It was a big fire.

It took the length of time a person can grill a turkey sandwich for the smoke detector to go off.

The stove was here, I was grilling the sandwich, there was a dog begging for the sandwich, and I did what you normally do when you're grilling something, and your smoke detector goes off, which is assume nothing is wrong.

- When I've been using my stove, it's commonly triggered my smoke alarm without real visible smoke.

And so, it's constantly a question every day that I go home, like, what am I exposing myself to?

What types of gases, and what types of particles in the air that I can't see am I exposing myself to that's making my throat hurt, that's making me wonder for months do I have COVID?

- So, there were two kinds of detectors, and there's also two kinds of smoke, to simplify it.

In flaming fires, they tend to give off small particles.

Studies have shown that the ionization detector, because of the way it works, is very sensitive to say, particles less than one to two microns.

The photoelectric is better at detecting the smoldering fire, which gives off larger particles because of incomplete combustion.

So, almost everyone's asleep during a smoldering fire.

That's when you need the smoke detector, and several studies as far back as 1980 in LA showed that sometimes the ionization may not go off early enough for you to get out of the house.

NIST did a massive study, which is online.

People can check this out.

The NIST Home Smoke Alarm Report.

And in that report, in the smoldering fires, the photoelectrics on average, I think, responded about 30 minutes before the ionization.

Now that in and of itself is not bad.

If they were responding 30 minutes earlier, but the ionization was still giving say, five minutes warning to get outta the house, I wouldn't care.

But many of the fire tests they ran, the ionization was going off too late, meaning the smoke was too thick to get outta the house.

If you could reduce the disabled detector deaths by half, that'd be a 10% reduction.

If you could reduce the people dying with a working detector by half, that's 20%.

So, if you reduced fire deaths in this country by 30% over the last 20 years, that's a lot of people.

- Wow, so great that your family was not here.

- Yes, it could have been so much worse.

Could've been so much worse, so one of the things that the restoration company has to do is bring everything up to code that is currently not code, and there were several things done by the previous homeowner that weren't up to code.

- The building codes haven't caught up.

For example, you have fire resistant construction.

We're not trying to prevent all house fires, but it allows for fire to happen in a building, and contain the fire to one room for either one or two hours.

Completely different than the interface fire problem where it's not containing the fire that is the goal.

The goal is to prevent ignition of the building at all.

Obviously, one method that we're most comfortable with is building code requirements.

You have to do it this way, or that way.

And the other prime driver is gonna be the insurance companies.

And, unlike Europe, they're not gonna be providing discounts.

They're on the road towards understanding the problem well enough that they can make very strict requirements, and regardless of what the government recommends, or what the codes require, you can't get insurance without complying with their standards.

The insurance pressure is coming, not in incentives, but in denying coverage.

- [Narrator] Big city fires have always gotten a lot of attention, with wildfires being largely ignored.

Take, for example, the Great Chicago fire of 1871.

We all know that one.

You probably didn't know that across the border in Wisconsin on the exact same night, the Peshtigo Wildfire killed over 1,500 people.

It's still the most deadly fire in US history.

- Wildfire is a natural hazard that can quickly become a disaster.

- And once we've observed a hazard like fire enough times, and in enough detail, then researchers can build experimental labs like the one behind us, so that we can simulate it.

- Yeah, and what they're doing in this experimental lab, and lots of experimental labs all over, which you're gonna see lots of in this season of "Home Diagnosis," is testing systems and products to see if they work in making a home safer.

- So that we can keep those hazards from turning into disasters.

Let's go inside.

- [Researcher] The biggest thing that we research here is how do the embers get carried by the wind all around the structure there, and interact with it in a realistic wind environment?

That's really important for us to study.

- It's a complicated name.

It's called the Wildland-Urban Interface Fire Problem.

At its most basic level, it can be defined by three elements that happen very quickly.

First, the fuel feeding a fire changes from vegetation to buildings, hence wildland-urban.

So many houses ignite so quickly that the fire department is overwhelmed.

During these disastrous interface fires, 90% of the buildings are destroyed once they are ignited.

So once they're ignited, nine times outta 10, the building's on the ground, completely.

- About 60 to 90% of the home ignitions during wildfires happen from the tiny embers that are generated by the fire.

They blow ahead of the fire, carried by the heat, and the winds that drive fires typically.

Houses can also ignite from direct flame exposure if flames can reach out and touch the building materials, ignite the building materials directly.

And then, in some cases, radiant heat.

And that's like the, you know, the heat that you feel from a campfire.

If there's enough of it, it can actually ignite surfaces.

- There's three things that people should really think about in terms of vulnerabilities of your home.

First and foremost, the roof.

You wanna have a class A roof, and you wanna keep it clear, because that ember lands on top of a bunch of pine needles, or something like that, now you've got a much bigger fire.

The Paradise fire, you know, a lot of pine trees, oak trees, and we saw a lot of gutter fires, because that material was deposited in the gutters.

Then we had penetration underneath the roof planes, because of gutter fires.

Basically, the town of Paradise was burned in a six hour time period, with a continuous wind, and with resources basically dedicated solely to getting people out of harm's way.

What we found as the strongest predictor of failure, or loss of an individual building, was the distance to the nearest lost structure.

Meaning that if your structure was within 50 feet of another lost structure, the likelihood of failure was very high.

- The second is your vents.

Roof vents, crawl space vents.

You want those to not allow large embers to penetrate.

- So, a top priority is to create a shield to keep out embers and flames from vented attics and crawl spaces.

Kids, do not play with fire without your parents, and you're awesome for watching this channel.

- A huge advance in the fire safe technology here is intumescent coatings, which work something like a bulletproof vest.

They don't sag away from the heat of flames, they actually swell up and create a firewall if the wildfires flames get close enough to the house, which we hope doesn't happen.

- And then third, critical defensible space.

The wind interacts with normal size homes such that it creates an eddy at the bottom that's about five feet.

So five feet from the wind, five feet from the heat, from something burning next to the home.

- And if you're sitting inside your living room, or your kitchen, you can now see the flowers, as opposed to only seeing it when you drive up to the house.

Planting groups are in islands, they're not connected to other groups, there's not combustible mulch between it all.

They're separated from the house.

The trees are limbed and pruned, and I think it can be very beautiful.

It's just about looking at it a little bit differently.

- The buildings that survive these interface fire disasters survive by not igniting, or having very limited ignitions.

So, after cleaning, the homeowners go right back into their houses.

- This can feel overwhelming.

The wildfire program can feel heavy, especially when you try to think of it in finding a finite solution.

Even taking a small step today, even if you can't do everything to make your home fire resilient, fire adaptive, any steps are good steps towards creating that safer community.

- On the flip side, wildfire can be quite good.

Many of our ecosystems are adapted, or dependent upon wildfire.

There's a lot of good fire doing good work out there.

We're never gonna stop it.

We just have to figure out how we learn to live with it, how we can mitigate some of its damaging effects, and how we can enhance some of its positive effects.

I think that will be the success.

- You know, when I talk to foresters, they often talk about good fire, and bad fire.

Where good fire is controlled, prescribed fire, and bad fire is wildfire.

There's no such thing as good smoke, and bad smoke.

There's maybe less smoke, and more smoke, but all smoke from burning on the landscape is harmful to human health.

Hopefully, when you're doing prescribed burning, the conditions are favorable, and that burn is not gonna get out of control.

And it does mean that it tends to happen in cooler, slightly wetter weather.

It also is amenable to what we call smoldering fire versus flaming fires.

So, different stages of the combustion process.

And smoldering fire does create more smoke, because the combustion is less complete than during a flaming fire.

There's quite a lot of evidence now to show that on a per mass basis, the smoke from smoldering fire is more toxic than the smoke from flaming fire.

It has a lot more different stuff in it, whereas the smoke from flaming fire is more elemental carbon.

- An analogy can be made between the interface fire problem and the high-rise fire problem.

You can't evacuate everyone at the same time in a lot of these buildings, and so you have what are called fire refuge areas in high rise buildings, especially for people with mobility challenges.

So there needs to be communities with two ways in, two ways out, and the ability for fire apparatus to get into a community while the whole community's trying to evacuate, but also look at sheltering in place, which is a concept that the Australians have had years of experience with, and developing fire refuge areas.

- There are many facets to the wildfire problem.

We need to turn the dials on all of them.

The emergency alert system, the evacuation system, where and how we build.

How do we protect critical infrastructure, you know?

Our water supplies, our hospitals, schools, and facilities, they all need special help.

And how do we choose where and how to live?

- So when I first moved to Fort Collins, it was the day of the Marshall Fires.

We had a 100 mile per hour winds, and the apartment I was supposed to move into was in the line of fire.

I took a duffel bag of stuff outta my car, moved my animals in, and then we had to evacuate.

You know, coming back, and there's nothing there.

There were like, you know, shells of a car, or just someone's fireplace still standing.

It was, and then the next day, it snowed.

- The Marshall Fire, a December 31st, 2021 fire.

You'd think it would be a safe time of year.

That fire was eventually extinguished 12 hours later by snowfall.

And what we saw there was a grassland fire, not something where you'd see a lot of ember movement, necessarily, but grassland connection to wooden fences, and wooden fences igniting, and then being able to wick the flames directly to buildings, and then attached fences then basically burning adjacent to buildings, and creating an ignition point inside the building.

Every fire burns in a different fuel type.

And these are not the kinds of embers that will make it through someone's vent, because they will just extinguish themselves as they're blowing in the wind.

But as you start to get bigger pieces of fuel, they can burn for a longer time, and they can cause more damage.

And so if a two by four gets picked up and dropped, it's gonna burn for a long time.

So all of this matters when we kind of bring in the fire science, and we are trying to think about the individual product, and how the building is assembled, and what it's being asked to resist.

- In 2016, there was this major wildfire in Fort McMurray.

I think about 20% of the homes were destroyed.

The local government agency tested the soils, and they found high levels of arsenic, and that might stay in the home in dust, and it could be a cancer risk.

In pressure treated wood, very often the wood is treated with chromium, copper and arsenic.

And when the wood from the deck, for example, gets burnt, that can release the arsenic into the environment.

So the ash can be pretty light, it can blow around, and so it could go in through air exchange like through your window, or through your air handling system.

It could also be tracked into your shoes, and you can bring it in that way.

I think what we have learned from our study is it is possible to clean to a point, wiping down the surfaces, cleaning off the dust.

We would have very low health risks.

However, we did not do our study immediately after the fire.

And so we know very little about what happens the day that you move back home.

So I think in the future, if we can gain more understanding, then we can give better advice to people as they are going back after evacuation.

(gentle music) - When a wildfire enters a community, it starts jumping house to house, or building to building.

And as those buildings burn down, or are destroyed, they become mini water fountains, and when we have too many water fountains, what happens is we don't have enough water pressure.

And so, the water stops coming outta the houses, and now you have a direct line from the the debris, or the the vapors, or the smoke, into the drinking water system, because there are no backflow prevention devices between the homes, and the distribution system.

Well, during disasters, what also happens is you lose power, and you use communications.

And so when you lose communications, you can no longer understand what's happening in your water system.

During the Marshall Fire in Boulder County, Colorado, they had to physically get in vehicles, and drive through the active fire zone, climb up tanks to inspect, to figure out how much water they had left.

The city of Lewisville almost ran outta water.

They made a decision to bypass the water plant, and send lake water directly into their distribution system, right?

So the whole concept of water treatment is we wanna remove the organisms, remove the chemicals, and make that water safe.

But Lewisville bypassed the treatment plant, and sent the water to the firefighters through fire hydrants.

If they hadn't done that, you might've seen thousands of more homes destroyed.

East Boulder County Water District had their natural gas shut off, so they couldn't push water into their system.

Many of their customers live on a mountain, so the water goes up the mountain, and when they stopped pushing water, all that water drained down the hill.

And when they went back to repair it, they had to open fire hydrants for two hours, and have air come out, because that's how far away the water went.

So they had to bring it all the way back up the hill, and that is depressurization, and contamination.

- We're still trying to figure out exactly what are the mechanisms by which landslides are triggered after wildfire.

There's a couple hypotheses.

One is the formation of what's called hydrophilic elements, or oils.

These are essentially oils in the plant leaves that burn, and are deposited on the ground surface, and they serve as a waxy barrier that prevents subsequent rainstorms from infiltrating into the ground.

And in consequence, you have a big pulse of water that reaches hollows, and then that big pulse of water can very quickly turn the ground in those hollow areas into these fast-moving debris flows.

- So when a fire happens in your home, the other thing that happens is your home gets flooded.

- Yeah.

- So was it a total loss?

- It was called a freestanding loss, which basically means the amount of damage done exceeded the amount of coverage covered by the house.

My neighbor directly across the street co-owns a restoration company, said this side of the house can be saved, cleaned, and repurposed, so that side of the house could be rebuilt from the foundation up.

And that's the only way that we weren't forced to sell is that he was able to pull that off.

- Flame retardants retard the combustion process, just like wet wood as opposed to dry wood.

So, they tend to produce smokier fires.

The type of self-contained breathing apparatus that firefighters wear today really didn't exist until the late '70s, and very few firefighters would wear their mask during the '50s, '60s, and into the '70s.

I came on right at the transition, but we didn't have enough, so as the youngest kid, I had to wear the old heavy mask, and it weighed about 40 pounds.

Well, that's a lot to carry when you're also dragging hoses, and working tools.

So, the older guys, they'd run to the front door, and if they could smell that it was a cotton smoke, they'd say, ah, don't worry about it, let's go in.

And if it was, they'd say it's plastic, put your mask on.

And it's sort of fascinating.

So like, you have a cigarettes and furniture problem, and the CPSC says, we're gonna tell the furniture industry to make furniture that's resistant to smoldering fires.

Good idea.

Furniture industry says, okay, the way to do that is to get rid of the cotton batting and go to polyurethane foam.

Okay?

Well, the problem with polyurethane foam is it burns a lot faster than cotton batting, and so flashover occurs in say, four minutes instead of eight minutes.

So now let's put flame retardants in the furniture.

So, you've solved one problem, created another.

- Flame retardants.

They're organic chemicals that have been added to a wide range of products and commodities to reduce the flammability of that product.

But I wanna quickly add that there is scant evidence of the benefits that flame retardants actually do reduce harm.

That is, harm from fires.

So, evidence of harm from exposure to flame retardants.

Scant evidence that flame retardants are actually effective at reducing harm from fires.

- So testing by the CPSC and UL show that it doesn't make a difference.

The TB117 couch, and the non-flame retardant couch, when you put a match to them, they basically burn exactly the same.

Why?

Because in a real fire, it's not like you're cutting open the fabric to expose the foam, and then some kid's putting a match to the foam.

That's not what happens.

The fabric is catching fire, and by the time it gets to the foam, it's not a little flame, it's a big flame, and the test would only stop burning from a small flame.

So in the real world, it didn't make any difference, probably.

As one researcher said, we made a test so they'd have to put in just enough flame retardants to give us cancer, but not enough to stop the fires.

What we may have done by adding these chemicals to the furniture has not necessarily changed the heat release rate because the test they were designed to pass didn't mimic real life conditions.

We may have just had them produce more smoke, and the smoke they did produce was more irritating, which actually shortened the time for people to get outta the house safely.

- Most of us spend the vast majority of our time indoors, at least 90% of our time, and that's pathetic, but it's also just an indicator of real life in the modern world.

And the indoor environment can protect us, or it can put us at risk.

It can do both of those things.

So, the ability to keep wildfire smoke out of the indoor environment, the ability to keep the indoor environment at a comfortable, safe temperature, the ability to keep the indoor environment dry, all of these risks that we're facing as the climate changes, we need to be evolving the indoor environment to keep us safe from those risks.

- The evolution has begun, whether we like it or not.

- Fires are just the start for us.

Over these 11 episodes, we'll dig deeply into the science of many other disasters, and how to avoid them.

- This season is not here to scare you, though you may get that feeling.

This research will help you prepare your home for the 21st century.

- To learn more about fire safety, and all the other hazards we're navigating this season, visit homediagnosis.tv.

See you next time.

(tense music) (tense music continues) (tense music continues) - [Narrator] "Home Diagnosis" is made possible by support from Broan NuTone.

Better air, better life.

By the Got Mold?

test kit.

Real science, real simple.

By AirCycler, RetroTec, Rockwool, and RenewAire.

By generous support from these underwriters, and by viewers like you.