Water Storage Tank Liners 2

[erlee]

I have a project that would require lining a water storage tank (for potable water). The water storage tank is steel, bolted, and epoxy lined. The tank leaks at the gasket, between the bolts. I was wondering if anyone has any experience with "spray-on" tank lining epoxy, if so, what are the advantage and disadvantages? A couple of companies I was looking at are at the following links:

http://www.cimind.com/

http://www.ravenlining.com

 

[cub3bead]

Are you wanting to put this lining in your existing bolted tank? If so you may not get the results you seek.

The rubber gasket between the plates will flex due to changes in water depth and ambient temperature. Epoxy linings tend to be very hard and would crack in this application.

Is the bolted tank manufacturer not standing up to his warranty? If you want to fix your leaking tank have you considered using RTV silicon to caulk the gaskets to the tank walls?

Epoxy linings in welded steel tanks are a good alternative.

 

[Zambo]

There are also butyl rubber liners available, shaped to the size of the tank. Try Franklin Hodge

http://www.franklin-hodge.co.uk

Zambo

 

[jherbert]

Rubber gaskets surely not?

Rubber was banned as a material in
potable water systems many year ago,
because it supports Legionella
proliferation. If those gaskets are
indeed rubber they need changing.

Regards,

 

[bimr]

I agree with jherbert. Why don't you call the tank fabricator and have him fix the problem.

 

[BRIS]

If it is a segmental tank with internal bracing then you can't fit a butyl liner.

 

[layfieldman]

Have you considered a drop in flexible tank liner made of a water potable (NSF) rated polypropylene?

 

[BRIS]

A flexible tank liner is not a feasible solution for a segmental tank with internal bracing.

The only solution is to remake the joints.

Brian

 

[erlee]

Thank you all for your comments. To give you some information, the tank was constructed, and within the warrenty period, the company went out of business. It was passed to another company, but there didn't seem to be much interest in pursuing issue. Now the warrenty period has passed and I have inherited the system. The steel bolted tank is braced on the exterior, with a gasket between the bolted parts. I am considering a flexible interior liner. However, I was just curious if anyone has had any experience with the spray on type of liner distributed by these companies (see websites):

http://www.cimind.com

http://www.ravenlining.com

or any other.

 

[layfieldman]

Our company does work with spray on liners and they work very well for what they were designed. The one we use was a polyurea spray on. It is great for when you have lots of penetrations (pipes, piles...) but is very expensive. If they installers don't know what they are doing then you may have quality control issues as well. If you decide to go with a spray on make sure they do density (thickness) testing in a regular pattern. Other than that I believe that the spray on is approximately twice as much as a fabricated flexible liner installed. This is taking into consideration of having to sand blast the interior prior to spraying for a good bonding surface.

 

[jherbert]

hi layfieldman,

Do you or your company have any
data for the relative Legionella
growth/proliferation on that
polyurea material?

cheers,

 

[bimr]

There is no way any of those coatings are going to work. How do envision bridging the coating over joints between the plates? Do you really expect the coating to adhere to the gaskets? What about all of the cracks and crevices? How do you expect the coating to adhere to the smooth coated plates?

Most spray applied products depend on surface preparation for success.

Whatever the case may be you should speak to someone who specializes in coating the type of tank you have and has seen the application years later to determine strength and durability of the product.

 

[layfieldman]

The other way to make the coating work, besides sand blasting the surface for preparation, is the preline the inside of the tank with a light weight geotextile (hang with flat bar anchor at the top of the tank) and spray directly onto the geotextile. Our company has used this method many times in the past and it works well.

 

[flexman]

What size is the tank? Is it covered? I suggest you install a prefabricated flexible membrane liner of potable water contact approved material. There are several such flexible membranes and several firms who can prefabricate the liner and several firms who can install the liner.
Good Luck
flexman