sewer tank

[ocweld]

HI guys Dan their is two man holes on an sewer tank take a bar and drive it in to the ground unit you hear a ping nose and their is a bended chuck of rebar to make a eyehole for the sewer guy to put a hook throw and take the lid off

[croyall]

Ventilation is Key

I work for a local wastewater treatment facility. If you rent a ventilation fan you can pump fresh air into the tank to remove any methane. If you do not ventilate you will definitely have a methane problem. We vent all tanks for at least 10 minutes and we do any type of operation necessary. One precaution also is make sure they have not flushed any flammable liquids.

[Mark Lindquist]

Mark

After doing industrial refrigeration and rebuilding very large boilers for 30 years the most important thing iv'e learned is it's not worth it taking any chances. If it takes a couple of hours longer at least you are still healthy and can work yet another day. Its also important to let the younger people know the value of safety.

[pipeline Dan]

how thick should I go??

Thanks guys for all the info, well this is what is up with the tank, the sewer tank is made from fiberglass and is in the parking lot of a Honda dealership, so the tank itself has a 5'x5' steel frame that sits in the ground and is flush with the parking, lot they have a piece of 1/4 plate steel(no supports) as a lid and of course a trailer full of cars came in and the semi drove over the plate and its bowed real bad. Is there a rule of thumb as to what i should be using when I choose the thickness of plate? with it being 5'x5' its a good size hole and sure as heck if the tank below cracked I'd be the one to blame. I was thinking that a 3/4" plate and say 2x 2x 3/8ish angle for underneath supports and around the hatch that I am cutting into it should be enough??? Have any of you guys ever done this type of thing before? I am always open to friendly advice

[pipeline Dan]

how thick should I go??

Thanks guys for all the info, well this is what is up with the tank, the sewer tank is made from fiberglass and is in the parking lot of a Honda dealership, so the tank itself has a 5'x5' steel frame that sits in the ground and is flush with the parking lot they have a piece of 1/4 plate steel(no supports) as a lid and of course a trailer full of cars came in and the semi drove over the plate and its bowed real bad. Is there a rule of thumb as to what i should be using when I choose the thickness of plate? with it being 5'x5' its a good size hole and sure as heck if the tank below cracked I'd be the one to blame. I was thinking that a 3/4" plate and say 2x 2x 3/8ish angle for underneath supports and around the hatch that I am cutting into it should be enough??? Have any of you guys ever done this type of thing before? I am always open to friendly advice

[lynx_welding]

i know that us guys like to go hard core and heavy on material but 3/4. i would say since they are using 1/4 already. and it bent. i would say use 3/8 and cross bend it a little. and then build the frame in under neith . i just think 3/4 is a bit much. your access would be shot trying to get it off the ground or out of its frame. i think 1/2 would even be lots gimme a shout if you need anymore help

[DSW]

I want to say most of the road plate we have used to cover trenches on street jobs is 1" thick. We rent the plates so I don't have the plates to measure right now. 3/4" is probably the minimum thickness.

All the concrete tanks in parking lots we use are specifically designed as drive on tanks, as opposed to the standard concrete tanks.

I would check and see how big an opening this guy wants. I would make it as small as you posibly can to limit the weight on the opening if posible.

[redintn]

Well look at the next road crossing where they cut the road to put a pipe under the road and put steel plate down for traffic to cross till they fill in the ditch.
Some of that stuff is 1" thick.
Plan for the biggest load you can think of, because if it falls through, they WILL come after you.

[Wheelchair]

PLEASE have the tank tested by a chemist. I lost 3 friends on a saturday morning many years back just because an upper management person had to have the sanitary tanks cleaned and he could not wait until monday when a chemist would have been available and needless to say when the guys got to the bottom of the tank it was full of gas. A supervisor tried to hold an air hose to his face to try and get to them and about halfway down the ladder he passed out and fell to his death. This was a day that I will remember the rest of my life.

Again, please be safe
Wheelchair

[SundownIII]

Dan,

5'x5' is a "very" large opening for access to a septic tank.

I would first attempt to determine what the minimum opening could be.

Rather than go to 3/4" plate and reinforcement (would need a wrecker to lift the plate), I would go with about 3/8" material and brace it on the underside with 2"x2"x1/4" angle on 12" centers. That would give you more than adequate strength (even with the 5' square opening) for anything that can go over the highway legally. The backside reinforcement will give more structural strength than simply increasing the thickness of the plate.

You didn't mention how much space you had between the supporting framework for the cover and the top of the tank. I'm assuming that you have at least 3" of clearance.

[Cornerstone]

Thanks guys for all the info, well this is what is up with the tank, the sewer tank is made from fiberglass and is in the parking lot of a Honda dealership, so the tank itself has a 5'x5' steel frame that sits in the ground and is flush with the parking lot they have a piece of 1/4 plate steel(no supports) as a lid and of course a trailer full of cars came in and the semi drove over the plate and its bowed real bad. Is there a rule of thumb as to what i should be using when I choose the thickness of plate? with it being 5'x5' its a good size hole and sure as heck if the tank below cracked I'd be the one to blame. I was thinking that a 3/4" plate and say 2x 2x 3/8ish angle for underneath supports and around the hatch that I am cutting into it should be enough??? Have any of you guys ever done this type of thing before? I am always open to friendly advice

Call your friendly neighbourhood engineer. I would.

[c wagner]

Call your friendly neighbourhood engineer. I would.

Good advice, I agree.

[Coalsmoke]

Call your friendly neighbourhood engineer. I would.

I agree, or if not then as mentioned above 1" as is used in road plate and find a good way to anchor it.

A cement truck out here bent and fell through a make shift road plate and it made a **** of a situation trying to get it out of the hole being full of cement that was setting up and heavy as sin. I don't know who got the bill for that, but I'm guessing it didn't go over well.

[davedarragh]

Concrete Weight

Yes, a mixer is VERY heavy. On the average, 1 cubic yard weighs 4,000#. The new trucks (down here) have 11 yd drums = 44,000# of mud. I drove a mixer for 10 years, and the first thing all of us were taught, where's the septic tank? A fully loaded 6 axle mixer is 76,000#. A full load of cars can be 80,000# (even though the weight is spread out more). In these economic times, car dealers are suffereing from sales, so BEWARE, they may be trying to "cut" the preverbial corner (or septic cover). I don't know about in Canada, but down here, even though it's considered "private property," it's still a "public" business, and is subject to ALL Municipal Building Codes.

Dave