(a) Operators advise that the valve life is being extended by at least 2 - 3 times. An average life is 6 to 8 months on high use heavy oil valves. Very few valve changes reported on Enviro Vault equipped tanks.

New 4 inch valve	$300.00 - $450.00
Labor to replace valve	$100.00
Vac truck to pull fluid down to enable valve change (if unable to utilize valve change plug)	$200.00 - $300.00
Total cost:	$700.00 - $800.00

Prevent frozen valves as they are kept warm inside the vault through heat transfer from fluid within the tank. Costs for existing methods of insulating exterior valves can be as follows:

(b) Initial cost to insulate valves with fibre glass; $75.00 to $100.00 (for a 4 valve tank). Fiberglass insulation eventually gets soaked or breaks down offering little insulating value. Every 2 years it must be removed and replaced with the old insulation disposed of at a landfill at a cost of $75.00 - $100.00 per change. Some valves have to re insulated every year.

(c) Apply urethane foam; $80.00 to $100.00 per valve, a 4 valve tank = $400.00.

There is still the possibility of valves freezing even when insulated.