VIDEO: Here’s what happens if there’s a fire in the Highway 99 tunnel

| Alaskan Way Viaduct | Highway 99 tunnel | West Seattle news

That’s video from WSDOT, recorded inside the Highway 99 tunnel during a first-of-its-kind test today. From WSDOT’s project spokesperson Laura Newborn:

This morning, Seattle Tunnel Partners, the contractor for the SR 99 tunnel, successfully completed the first test of the tunnel’s deluge sprinkler system. In this two-minute test, 6,400 gallons of water poured out of the overhead sprinklers along a 216 foot section of the upper road of the double-deck tunnel. The tunnel is divided into 208 fire safety zones and the fire suppression system is designed to activate sprinklers within the safety zones – or more simply, at the point of a fire. Today’s test spanned two safety zones.

Seattle Tunnel Partners has many more systems tests and safety tests ahead before the tunnel is finished. After all tests are complete and all tunnel systems are a ‘go,’ WSDOT must close the viaduct through Seattle to finish building ramps and realign SR 99 into the new tunnel. Given the amount of testing still ahead, it remains too early to give an exact date for tunnel opening, but the tunnel could open to traffic as soon as this fall.

As we reported after covering a media briefing near the tunnel’s south entrance last week, Highway 99 between the West Seattle Bridge and tunnel will be off-limits to downtown-bound traffic for up to two extra weeks beyond the viaduct-to-tunnel transition closure, to finish the main route into downtown.

SoAdmiralK June 28, 2018 (6:13 pm)

SOOO many reasons to hate the tunnel.

KBear June 28, 2018 (8:29 pm)

You think the 1950s viaduct and Battery Street Tunnel are safer? Or do you think the fact that it has a fire suppression system is evidence of its unsafeness? I guess all modern buildings are unsafe then.
- dsa June 28, 2018 (8:48 pm)
  
  Between the two, I’d drive the old viaduct. I don’t know if I’ll drive the tunnel yet.
- 22blades June 29, 2018 (7:35 am)
  
  The Battery Street “Tunnel” is technically not a tunnel. It’s just a ditch with a grated cover; sorry I forgot the technical term for such a design. It’s naturally ventilated up into the condos above it.I still think they should repurpose it for something (at the very least precious parking) instead of filling it with rubble. I think the argument for seismic requirements is BS.
  - dsa June 29, 2018 (11:35 am)
    
    It could have been repurposed as an under surface city street. Near each of the ends instead of using the existing portals they could have cut the surfaces and ramped up to grade.

Chris June 28, 2018 (7:04 pm)

Free carwash…love it.

Ralph June 28, 2018 (7:40 pm)

So car fire in the tunnel… Flammable liquids (ie. Gasoline, motor oil, etc.) + water = disaster. Great job Seattle/WSDOT! Way to go! Consistent engineering throughout all your projects.

WSB June 28, 2018 (8:30 pm)

What would you recommend otherwise? From online references: “Deluge sprinkler systems are the most common fixedfire fighting system (FFFS) used for traffic tunnels.”
Jon Wright June 28, 2018 (9:04 pm)

Internet commenters are armchair experts in a wide variety of subject matter.
very smart June 28, 2018 (9:41 pm)

Honestly once you have a fire in a tunnel the whole thing is toast. Best to seal it up immediately and start work on a completely new tunnel to replace it.(Source: have a several diplomas in Tunnel Fire Solutioning–in fact just got my third degree)
- Question Authority June 29, 2018 (11:16 am)
  
  By the use of a deluge fire suppression system the fire will not reach critical temperatures to compromise the structural Integrity of the tunnel. The only degrees that matter are the ones in Fahrenheit, not yours.
  - Nerdy June 29, 2018 (2:45 pm)
    
    I think Very Smart was just being sarcastic. Everyone knows that you don’t seal up a burnt tunnel. You fill it with gravel. Oh, look at that, I just earned a diploma in Tunnel Fire Solutioning too!

dsa June 28, 2018 (8:45 pm)

Fixed foam was installed in the I-90 tunnels in Seatte and Mercer Island, but were considered not satisfactory and never activated to standby status…de activated, turned permanently off.

wscommuter June 28, 2018 (9:30 pm)

Bless all you tunnel haters and anti-tunnel “experts”. I appreciate that you’ll stick to other routes and make the tunnel less congested for the rest of us. Happy trails.

dsa June 28, 2018 (10:37 pm)

Not a tunnel hater at all, but that one scares me.
- Jon Wright June 28, 2018 (10:51 pm)
  
  What do you find scary about it?
  - uncle loco June 29, 2018 (4:14 am)
    
    The cost overruns.
  - No blind faith June 29, 2018 (6:01 am)
    
    Around 200 ft below sea level with no way to surface besides entrance and exit. But, it does have staircase to other level of tunnel. Woo Hoo!
    - heartless June 29, 2018 (8:24 am)
      
      I mean, sure, but plenty of people take airplanes and boats, both of which are rather lacking in terms of exit plans.
      
      I get not liking tunnels, claustrophobia, hard to hold your breath that long, etc., but I’m not sure avoiding them really increases your life expectancy…
    - KM June 30, 2018 (11:09 am)
      
      One of my favorite commutes was the East Bay BART tunnel when I lived down there. The rails get loud, but it was really great.Im always baffled at what people perceive as more dangerous on unsafe (underground tunnels) compared to what actually is (driving).
    - dsa June 30, 2018 (12:28 pm)
      
      KM, car, truck and MC drivers are a part of the unsafe issue. BART type tunnels are fine.

dsa June 29, 2018 (12:24 am)

A combination of alignment, depth, length, escapement and did you notice the thickness (thinness) of the upper deck? It did not look real strong. Give it time to prove itself.

Jon Wright June 29, 2018 (10:27 am)

Do you have any sort of engineering background that would qualify you to evaluate the fitness of the tunnel?

ltfd June 29, 2018 (5:05 am)

The tunnel that should scare you, if you ride the Sounder to the north (or respond to emergencies), is the Great Northern (railroad) Tunnel from South Washington St to Virginia Street. One mile long with no emergency exits, no emergency lighting, no fire suppression system, no ventilation system. It was a great engineering feat for its day, but it is a bad place to be during an emergency.The SR-99 tunnel on the other hand is very well designed with robust fire & life safety systems. While the fire sprinklers do not have foam solution for flammable liquid fires, the deluge design will still control heat release rates, retard fire progression, and create a survivable space in the tunnel – unless you are inside the immediate fire area.

Sassy June 29, 2018 (7:03 am)

The tunnel is blocks away from the Seattle Fault, and on the water side is the seawall and Elliott Bay.What’s the plan for the major quake that is coming? It’s not an if, but a when. What strength of quake is the tunnel designed to survive?Would the seawall be breached and the tunnel flooded?That’d be a reason to be leery….I’d like to hear the engineering overview on those concerns.

heartless June 29, 2018 (8:29 am)

Well, here.

SR 99 tunnel design
Beyond these generally earthquake-resistant traits, the SR 99 tunnel has been specifically designed to withstand a 9.0 magnitude earthquake. This magnitude earthquake only occurs every 2,500 years on average.

The design team had to ensure the tunnel could remain watertight after a seismic event to allow for the safe evacuation of people. Flexible joints between all component parts can accommodate an earthquake’s movements, and every piece of equipment to be installed in the tunnel has undergone seismic analysis.

All in all, the tunnel and operations buildings were designed to meet 18 different seismic codes, standards and specifications from around the country. So while you might not be able to plan where you are when an earthquake hits Seattle, you may take comfort in knowing this: The tunnel was designed with safety in mind, not only for day-to-day operations, but for the day “the big one” hits.
- dsa June 29, 2018 (10:34 am)
  
  I looked up your WSDOT reference and am quoting this from it: “underground structures are safe because they move with the soil, ” I won’t bother defining the word Fault. We have all seen enough pictures.
  - heartless June 29, 2018 (11:03 am)
    
    I mean, ok?
    
    I guess I’m not sure how to respond.
    
    I get that you don’t feel the tunnel is safe, but there seems to be a fair bit of engineering and scienceing (I know, I know, not really a word) behind it, and from what I can gather tunnels seem to be much, much safer than bridges or elevated roadways during earthquakes.
    
    Heck, I’d wager during an earthquake it’s even safer to be in a tunnel than on surface streets (away from falling debris, shattered glass, etc.).
    - Kara June 29, 2018 (11:44 am)
      
      We live in a world where facts don’t matter its just all opinion and the comments on WSB have gotten so hard to take these past few years. Although West Seattle was my childhood home I barely recognize it in the comments these days.
    - Jon Wright June 29, 2018 (1:47 pm)
      
      My opinion is just as valid as your fact!

sam-c June 29, 2018 (9:07 am)

So when they open the 99 tunnel, I wonder if we’ll have fewer 99 closures for marathons ? Won’t have all the viaduct closures for inspections! That will be nice

Douglas June 29, 2018 (4:13 pm)

Is there a plan for disabled individuals and their devices to be evacuated to the upper level deck, via the egress emergency exits? Is there any other method than a staircase? ramp? elevator?

dsa June 30, 2018 (11:38 am)

Douglas, if a person can even get their wheelchair out of their vehicle (lifts require 8 feet clearance), the pathway on the narrow shoulder will likely be blocked by cars doing what they do when drivers panic.

Sorry, comment time is over.