MemberJuly 10, 2018 at 12:00 am
Not mine, really. Just where I work. I did it. It blew up because of something I did.
FIRST, PICTURE THIS IN A RESTAURANT KITCHEN:
One of those half-wall setups (about 5’ high) with a hot-line on both sides of it. Cooking equipment on both sides, under a common hood. Electric, gas and steam heated equipment. All three energy sources pass through that wall.
The half-wall was once just a tile wall (still there underneath) which got upgraded with a stainless-steel skin and top-cap a few years ago for sanitation purposes.
A Blodgett oven I was working is located at the end of the cook line on one side of that wall. A 115v outlet for it was a whole arm’s length away as I reached behind the oven to unplug it. I nearly had to rest my chin on the wall to reach the outlet.
WITH THAT WORD-PICTURE in mind, here’s what happened:
SO…I unplugged a Blodgett gas convection oven I was working on. I did NOT turn it off before unplugging it. That just didn’t seem like a big thing at the time. It became so, though.
With that Blodgett oven still drawing amperage (to run its blower motor and heating system), a small arc naturally occurred within the outlet. A tiny one. One not too different from…say – unplugging a TV while it’s still on.
When I unplugged it…
In a fleeting second, the wall’s stainless-steel top-cap BLEW up as the vertical skin of the wall BLASTED out.
THEN….it was over.
My ears were ringing as I suddenly found myself trying to assess what had just happened.
WHAT THE #$@% JUST HAPPENED!!!
Kitchen staff rushed in from all directions asking “WHAT HAPPENED!” My ears were still ringing as they all asked me if I was “okay”.
I was okay, as I tried to take the moment in…while observing a fog of dust emanating from within a newly opened, one-inch crevasse that once was just a seam in the wall.
WHAT DID I JUST DO?
NOW…to make a long story short:
I made a phone call to my boss that I just blew up a wall, we’re all okay and there’s no fire.
He shows up, assesses it all…and made more phone calls. Upper management shows up. More folks show up. EVERYONE SHOWS UP!
I shut off the gas. Electricians shut down all the power in that wall.
Next, we all agreed to move out all the cooking equipment (six ovens, two ranges, two fryers and other stuff). With that out of the way, we found a distinct, lingering smell of mercaptan (signs of a gas leak, but gas was OFF) from within an opening in the wall.
Before the afternoon ended, an outside contractor was set up to tear out the wall, replace all the internal gas pipes and put it all back together again.
We’re hoping that THAT section of the kitchen can be returned to service by next week. Meanwhile, the restaurant somewhat handicapped for losing use of that portion of their kitchen.
DEFINITELY not my normal work day!
MemberJuly 11, 2018 at 5:26 am
All I can say is WOW!! I’m glad no one was hurt. I’ve never been a fan of those kind of set ups only because I was usually the one that had to fix any leaks, inside the wall. Please update us with where the leak was found to be.
MemberJuly 11, 2018 at 8:52 am
Ectofix, having gone through a similar situation many years ago, IF, you had a ringing in your ears, YOUR NOT OK. The pressure wave from the rapid combustion does damage that you do not see. Or notice. Hopefully your company does annual hearing tests. Go see a medical specialist. There are also brain and soft tissue issues that do not manifest immediately.
A minor loss of hearing will increase over time due to you adding more volume to be able to hear. And not noticing when you are in a loud area. And good hearing instruments are over $5000 today.
We all know that gas leaks never go away on there own, but increase over time. It’s actually a lucky thing that you found it while small. Here Gas companies are required to do a leak survey every 2 years. But they are often overlooked. Or done to a minimum level. Like the tech sticks his head in the door with his sniffer, makes out the paperwork, and goes to the next one. Sniffer truck goes down the road at more than the 2 miles per hour the equipment requires so that someone gets a coffee break 5 min longer. Politicians can make laws, but that doesn’t mean they are followed to the intent..
BTW, there has been several hundred of similar explosions this year alone. Most not reported on, to the big ones like this mornings, or house leveling level. Heck, I flattened one and damaged 6 others in the sixties.when I pulled on a steel line with a backhoe.in a new development. .Fortunately I had gotten off and was next to the rear tire opposite side when it blew.
MemberJuly 11, 2018 at 10:09 am
Seriously glad to hear you are OK!
That could have ended so much worse!
MemberJuly 11, 2018 at 2:01 pm
NGA made a rule after that that meters could not be inside after that. Just by bending the steel line it pulled out of the meter inside the cellar. Filling the house with gas. I do not know the source of ignition, but is was Fall and the heat may have been on.
MemberJuly 11, 2018 at 5:56 pm
Thank you all for your sentiments. I suffered no enduring ill effects. Today was just a normal day…except for having to recite my story of the event a few times to inquiring minds who wanted to know.
When I went back to that kitchen TODAY, several in the kitchen staff asked if I was there to blow something else up! LOL!!!
Come to find out, that wall is hollow for only its top couple of feet. The rest (down to the floor) is poured concrete. The existing gas manifold is embedded in it, so can’t be pulled and replaced. As it stands, the main gas feed comes down from the ceiling to supply that. So a decision was made to simply abandon what’s in the wall and re-route the gas through a new gas manifold on the exterior of the wall.
All the contractors had to do today was simply put the wall’s outer skin back into place and fabricate a new gas main manifold (welded) to run the length of the wall. They originally told me it would be done after lunch. Up that point, I remained ready (with anticipated materials) for the inevitable “go-ahead” to re-install the equipment.
HOWEVER…somebody didn’t “measure twice” before making the manifold, so it had to go back to their welder a second time for modifications. It was looking like it wouldn’t get done today.
Maybe our 3rd shift guys will get it done tonight. Then – maybe NOT. If not, then us 1st shifters will deal with it tomorrow morning. The restaurant was in full swing today and had adapted very nicely to the inconvenience of losing their prep kitchen. So I think they’ll be okay.
MemberJuly 11, 2018 at 6:13 pm
That has to be one big operation if that line was just prep.
MemberJuly 11, 2018 at 7:15 pm
They DO use that area heavily.
That cook line (both sides) has two Rational combi-ovens, three Blodgett convection ovens, a two-battery set of Frymaster fryers, two full Vulcan ranges, a Hobart mixer, two large steam kettles and a tilt skillet.
Otherwise, the restaurant’s main line up front can cover allot of that while the prep kitchen is down. There’s no doubt that it’s an inconvenience, but the restaurant Chefs always learn to adapt.
There’s been occasions here when a kitchen lost ALL use of their steam table, but we’d show up to look at it and were denied any opportunity during busniess hours to work on it because they’re hopping. Ironically, they’ll actually call it in just when things get that way, then they tell us “NOPE” when we arrive. We can’t work on it.
That’s one great reason why we have a 3rd shift.
Hours later, I’ll walk through (I’m 1st shift) and they’ll have steaming pots of water set upon the griddles and stove tops to keep pans of food hot. All that stuff set up to serve as impromptu bain-maries. So…they’re dealing with it.
I’ve denied some r-e-a-l-l-y busy kitchens of their steamers for WEEKS while we awaited repair parts. Yet, they still cranked out the same food DAILY.
Obviously communication is crucial to keep the Chefs abreast of things. When they know the gravity of the circumstances, someone amongst them have contingency plans somewhere ingrained somewhere in their brains which must be employed in order to remain open for business. And…they DO.
This reminds me of about the inception of and our reliance upon the computer nowadays…and how it replaced our formerly primitive ways of of processing information.
Those of us (like you and me) remember when there was no such thing as a computer to get things done. As computers took over, all us old croggies always implored the newer folks to learn how it was all done on paper…in case the friggin’ computer crashes.
It was certainly more labor intensive back then. Far more time consuming and relied on the footwork of runners bearing inter-office envelopes, telephones and maybe fax machines. It once was all relatively modern for its time. TODAY, it’s just history. However, it can be still serve as an adequate backup to still get things done…if folks are trained for it.
I don’t see this situation in this restaurant as being too different from that.
MemberJuly 11, 2018 at 7:50 pm
Remember when you spent hours on the phone to order a part that took 2 weeks to get to you and was the wrong one?
MemberJuly 12, 2018 at 11:59 am
I’ve been in a similar situation, it’s not fun.
Glad you came out okay.
I guess the gas was just present due to a leak and then got lit by the spark from unplugging the unit?
MemberJuly 12, 2018 at 3:19 pm
I have to commend you guys on your quick response and extreme attention to every detail. I have been doing parts on the residental side for a little over a decade and just recently have entered into the wonderful world on commercial. WHen I have a spare moment during the day (few and far between), I find my self shuffling through a few posts and taking in as much as I can. It is definitely helping with terms and parts not so much used on the residental side. Basically, thanks guys!
P.S. Love the stories!
MemberJuly 12, 2018 at 3:27 pm
Correct, olivero. Just a tiny arc within that outlet from unplugging the energized 115v Blodgett gas convection oven.
What’s more, the air/fuel mixture had to be “just right”.
Natural gas has –
- a LEL (lower explosive limit) of 5% gas to 95% air. Any lower and the gas mixture would’ve been too lean.
- a UEL (upper explosive limit) of 15% gas to 85% air. Any higher and the gas mixture would’ve been too rich.
SO…a 5% to 15% gas-to-air mixture is the sweet spot. That had to be the conditions at the outlet when the gas ignited and the wall got blown open. There was no visible flame…and no evidence of ANY fire afterwards.
With the exception of people rushing in from everywhere, the disheveled wall panels & top cap…and dust emanating out the wall’s gaping wounds – TEN SECONDS LATER? It was like it’d NEVER HAPPENED!
MemberJuly 12, 2018 at 3:32 pm
It’s amazing just how fast some things happen.
I guess you just calibrate your burners so well that there is nothing BUT perfect mix ratio in your kitchen!
I’ve seen a lot, I’ve been in it a lot and its never fun, gas and electricity are both monsters that have to be harnessed, let em loose and you’re in trouble.
MemberJuly 12, 2018 at 3:33 pm
It’s true, and thank you.
Most times the guys on here respond faster than the manufacturers tech support and the answers I get here are 8 out of 10, more useful.
MemberJuly 12, 2018 at 3:50 pm
I meant to register earlier but haven’t had the time. Especially when it’s a thread about residential! HA!
MemberJuly 12, 2018 at 4:23 pm
Be well my friend. Keep that “concussion protocol” in mind. Glad you’re ok.
MemberJuly 12, 2018 at 4:52 pm
MemberJuly 12, 2018 at 6:30 pm
This whole thing makes me think back to a new-ish restaurant I did repairs in about ten years ago.
I needed to shut the gas off to a fryer. I pulled the fryer away from the wall, got behind it, grabbed the ball-valve handle and turned it. The WHOLE VALVE turned as it broke away from the wall. A flexline followed it from within the wall.
- CSST maybe?
- Is the entire cook line fed by valves connected to flexible lines from inside the wall?
Well. What could I do? I have no control over newer construction standards.
So…I simply cradled the valve in my other hand, shut off the valve and went about my business by repairing the fryer.
I DID tell the restaurant manager, but he didn’t seem too concerned.
MemberJuly 13, 2018 at 7:31 pm
We actually answered a phone and talked to the customer. Good customers had my home phone and pager number as well. The challenge was finding a phone out in the boonies to return the page.
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