Have a 10' diameter, 65' tall water tower. Need to weld a new fill pipe 3" diameter to outside. No problem, crane and manlift and off we go. Problem- we need to paint the inside of the tank where we make the welds at. No inside ladder and only a 2'x2' access hatch on the top. 20 years ago I would have ridden the ball down the access hatch from the top, and painted as I went (and I can't believe I'm old enough to say 20 years ago, considering I used to do stuff like that). Osha today won't even let you use bos'n chairs, and I actually think this is the ideal situation to use one. Bright ideas anyone? 2'x2' custom basket? I know I wouldn't fit in it. 65' extension ladder? Rappelling tripod from the access hatch? I don't know that I would trust the roof of the old tank to hold it. Fill the tank with water, throw someone in with a life jacket and paint as we let the water out? Call the OSHA man, and ask him if I can't use a bosun chair, how he wants me to do it?
Cut a an access hole at the base of the tank big enough to get the man lift inside. flange the access hole for later use.
If there is any access to inside of the tower, scaffold up the inside, to the 65' height.
LoL, take pictures and post please!
WEld on a 6" fill pipe 12" long . Then reach in and paint interior (through 6" hole) where you welded. Then reduce 6" pipe to 3" and cya later wheres my check!
The pipe is welded about 6" off of the tank with steel brackets every 10" or so up the tank. I wanted them to just cut the pipe loose and reuse the brackets, eliminating the need to get inside. But no, they want to weld new brackets to the tank also. Those welds as well as the top welds where the pipe goes in need to be inspected/ painted on the inside of the tank b/c its drinking water. Its only a 10' diameter tank, so I don't see us driving a manlift inside of it. And no- no large opening at the bottom to put scaffold inside, I think it's only a 2' round door. Sorry guys, I don't have any check worthy answers yet.
Crane op, this is a bit out of my area of expertise, but seems to me, even on a tank project like this, you are not the design engineer, the folks who own the tank would have to have someone do that. And even if they don't have one, if they're going to specify that you can't use the old mounts, must use new ones instead, and go inside tank to paint weld spots, then they must come up with a way (ladder welded to inside of tank or something) for you to do the work that they specify, no? I mean, we ain't born with wings.
what about an access hole at the bottom as stated before except just big enough to set a small manbasket inside....... drop the ball through the top hatch, hook up the basket do your painting and inspecting, unhook the basket .. ball out top, basket out bottom. and like was said before weld a flange to seal up bottom opening and have it all painted up ...... wheres my check? haha
i think rapelling down is the only option, 2 foot is not much wiggle room tho. tie the rope around the engeeners ankles &lower him down to inspect the welds, make sure the rope is long enough so he can get to the bottom ;-) lol then drop the rope!!
Very well said. It seems at times we as contractors are put into some "sticky" situations where we are tasked to undertake something that the engineer/designer either left out unintentionally or intentionally . Sometimes these "fuzy" details, IMHO, are left out on purpose or laziness, in order to shift liability to the contractor.:cool2 I try not to assume any more risk than need be on a project, Architects and Engineers get paid very well for their services and we as contractors should not be doing their job. Just my $.02.
And...sounds to me the owner is wanting crane op to absorb the cost of performing this "specification" that they have presented. They want new mounts, and want weld heat spots inside painted, the cost should be part of the contract.
sounds like a change order to me. No possible safe acess solutions.... sounds like your going to have to weld a ladder to the lid all the way to the bottom. 65' of ladder down through the hole with a safety tie off rope most likely stainless.
Yair . . . Umm, why would the fill pipe go in the top of the tank any way? There must be a reason but I can't figure out what. Why is this, does anyone know? Cheers.
Tell them they are going to have to lay the tank down... If they don't actually have to do it, the look on their face will be priceless!
Oh, and as a side note, if there is a 24" man way in the bottom, and the tank is 10' across, they can use tube scaffolding, as long as they have qualified scaffold erectors. If the only man way is the top, well then it would be a lot harder...
Need to CYA , who is going to issue the confined space permit . Who is going to provide or even operate the equipment to see is the air is safe . Most water has chlorine ,that may be a problem
With the pipe going in from the top it will create a air gap so there will be no way for a siphon to start. Also, if you put the fill pipe on the bottom and you get a leak in it you could be looking at massive quantities of water trying to/or will be getting out.
That's how it was explained by one water dept employee , Easier on the pumps and once water leaves the pressurized system they don't want a chance that something in a non pressure storage tank could contaminant the entire system
Yair . . . 95zIV. Those two reasons you mentioned are the only ones that I could bring to mind . . . there are probably other factors at play here but on a normal installation neither of them are legitimate concerns. I would suggest that filling into the bottom of the tank with a check (oneway) valve is normally a better design option . . . and a LOT simpler in this case. With top fill there are factors of splash and oxygenation and what all but we won't go there I have seen a case where a "professionaly" designed system utilised two 90 mill poly pipes to a one hundred thousand gallon installation on top of an escarpment . . . one came out the bottom for delivery and one went in the top to fill??? We are talking an extra half a mile of 90 mill. pipe for no advantage. Cheers.
Yair . . . oops! Tiny was quicker on the trigger, I was typing while he posted. I'll get back about the pump thing later unless some one beats me to it. Cheers.
the scaffolding could be built from the top down on the inside. just give the dimensions of the tank to a scaffold company. they will design a system to meet your needs. I used to build scaffolding about 30 years ago. the tube lock scaffolding can be built into about any shape you want.. Tube lock pipe starts a 4 feet in length. ________________ as mentioned you will need to ventilate and monitor the air
:falldownlaugh That's the way to play ball right there!
So I finally got a chance yesterday to look at the tank. Thanks for all the responses guys, I really appreciate it. I'm not the contractor, I'm just providing the crane to lift the pipe up, but the welder doing the pipe work, just calls me and says "hey, how we gonna do this?" I just charge by the hour while I'm there with the crane. The tank is actually closer to 80' tall (by my rusty trusty eyeball), and the pipe we're replacing is actually the overflow pipe. If they are pumping into the tank, and the shut offs don't work, this releases the water back out of the tank onto the ground. The tanks get inspected as public water systems, and if the pipe is rusty, it needs to go. The bad part is the inside inspection and painting of the tank. I'm sure they scaffolded it when they built it years ago, but they're gonna have a fit on what it will cost now. The ladder starts about 30' up the side-no cage- no rest platforms-so I didn't climb it to look for roof hatches, but from a distance I can see no hatches directly above the overflow pipe. The one picture shows the bottom access hole, thats my 2AA mag lite setting on it for a reference of size. I don't think my 11year old boy could fit through it. In the third picture, the pipe we're replacing is on the right, the ladder is on the left. Its also kind of handy having the power lines close for working. Thanks for the confined space comments too Tiny- that had slipped my mind also. I think the best option right now is welding/installing a new 3'x3' roof access hatch right above the overflow. Weld it in first, replace pipe, manbasket through hatch to inspect welds and paint, and paint underside of new hatch from on the roof.
Tiny, that's a great observation about the confined space. Not the best place to use can of krylon.
google the tanks address, you will get an overhead view of the tank. no need to climb the ladder
Call the inspector and ask how He intends to inspect the weld and paint.
How about an arborist saddle? Osha just approved the use of a crane to hoist a tree climber, I would think if you followed the standards you'd be okay. If you're interested send me an email and I send you a copy of the standards.