hanson pressure tanks
Specification #FI 1190
(Sprayed-On Polyurethane Foam With Topcoat)

All Hanson water storage tanks are offered with optional spray-on polyurethane foam factory insulation with topcoat. Nominal "R" value is R-16 @ 2" thick. This exceeds ASHRAE requirements.

Hanson factory insulation is a 2 component HCFC blown, polyurethane spray foam system. The foam is rated CLASS I according to ASTM E-84 at two inches, flame spread index 25 with 345 smoke developed.

The product is designed for use in applications where the stringent requirements for a Class I system must be met. Its outstanding physical properties result in exceptional fire resistance.

(Information taken from the manufacturer's product information and subject to change without notice)

Foam insulation is applied at ambient temperature, nominally 70° F or more and curing continues for several more days.  This is accelerated by extra heat, notably during system startup. The bond of the foam to the tank is also affected and the combination of the reactivated expansion of the foam and the weakened bond can lead to blisters forming in some cases.  To avoid this, it is important to bring the tank temperature up as slowly as possible, giving pressure in the closed cell foam time to dissipate.  Once fully cured, there should be no further problems. Make sure that the topcoat is good condition, it can be touched up with white roof coating if necessary.

Installed Density:

1.7 - 2.0 PCF

Compressive Strength:

22 -28 psi

Tensile Strength:

40 - 45 psi

R. Value:

7.11 per Inch (R-16 = 2 1/4")

Closed Cell Content:

Over 90%


2 lbs/cu ft

Max thickness:

4" (R -28)


2 coats (min. 23 mils D.F.T)
White elastomeric coating

Undercoat: (optional)

1 coat (2-3 mils D.F.T.) inorganic zinc primer

UV Resistance:

Excellent (ASTM D-1499)

Reflective index:



Excellent to 210 degree F (ASTM - 794)

Water Permeability:

Zero after 21 days immersion


58.7% by volume

Note: Hanson R-16 foam outdoor tank insulation is an effective alternative to metal jacketed tanks at about 70% saving for the same R. Value. Any minor shipping damage can easily be repaired in the field with no effect on performance or durability. As the foam is closed-cell, and impermeable by water, any pinholes noticed in the topcoat are cosmetic and do not affect the durability of the product. Due to the characteristics of the product, the actual expanded thickness of the insulation at R16 can be 3" or more.

Before system startup and periodically during service, the topcoat should be examined and repaired if necessary. We also recommend inorganic zinc tank primer at extra cost.

Although we offer this insulation system for outdoor service only, with the addition of a thermal barrier by the installer, it can be approved for indoor service in most jurisdictions.

Thermal barriers can be metal, cement, plaster or suitable proprietary materials with fire resistance properties equal to 1/2" gypsum wall board. Final approval of a thermal barrier installation is at the discretion of the local building code official.

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