SPF Density & Adhesion Testing



Unless otherwise specified, randomly choose an area, which represents the average application. In cases of dispute and where appropriate, obtain three specimens from each surface area where spray polyurethane foam insulation is being installed. The three specimens equally spaced are to be obtained from a 3 m by 3 m area chosen by the inspector.

Preparation Of Specimens

The specimens must be taken from the installation site and removed from the substrate upon which the spray polyurethane foam insulation is being installed. Remove any loose or compacted material from the specimens. Remove the top and bottom skin from the specimen by cutting a 6 mm slice from the top and bottom. Record the number of layers within the specimen.


The density of the specimen shall be equal to or higher than the minimum density specified by the chemical manufacturer.


After determination of the mass of the specimens, the volume shall be determined by water displacement. The density shall be calculated based on the values determined above.


A. An analytical balance, accurate to 0.01 g;

B. A knife with minimum 180 mm blade or a coring tool capable of cutting a sample; and

C. A graduated cylinder of minimum 1000 mL size with 10 mL maximum graduation.


Cut and remove three specimens (approximately 70 mm in diameter and 50 to 100 mm long) through the full thickness of the spray polyurethane foam from the middle of the test area.

Perform the following operations for each of the three specimens:

A. Without wetting the specimen, make sure that it is of the correct size to fit into the graduated cylinder. Cut into pieces or trim if necessary. Gently shake off loose particles;

B. Weigh the specimen and record its mass (in grams), ensuring that the minimum mass is 5.5 g;

C. Fill the graduated cylinder with 700 mL of water and record the volume (in mL);

D. Submerge the specimen completely using a thin-wall plastic tube, wire or other thin instrument and record the new volume(in mL) within one minute;

E. Calculate the water (in mL) displaced by subtracting the volume recorded in C from the volume recorded in D; and

F. Divide the specimen mass (in grams) by the water displacement volume calculated in section E, (in mL). Multiply by 62.4 to convert lb/ft³ then by 16.018 to convert to kg/m³.


The cohesive and adhesive characteristics of the spray polyurethane foam shall be determined as outlined below. The test specimens shall not show de-lamination or separation. The adhesion and cohesion tests should be performed on site with the specimen attached to the substrate.

Adhesion Test

A circular plywood disc equipped with a hook is bonded with an adhesive to the surface of the insulation to be tested. The spray polyurethane foam insulation is cut 70 mm in diameter through the full thickness of the insulation. A specified load is attached to the hook perpendicular to the surface, and any rupture is observed.


A. A Round plywood discs, diameter 70 mm, thickness 20 mm;

B. Two-component epoxy glue or a shot of spray polyurethane;

C. A tool made from thin wall tempered pipe to make 70 mm cylindrical cuts in the insulation;

D. Wires with two hooks (to be attached to the plywood discs or claw apparatus), wire length 600 mm;

E. A support frame for the test; and

F. A weight of 1 kg.


A. Select two areas in the middle of the test specimen and make cylindrical cuts through the entire thickness of the insulation;

B. Bond the discs with hooks and wire to the test specimen using two component epoxy glue or spray polyurethane foam;

C. Pass each of the other ends of the wire through a support and attach to a 1kg weight. The attachment shall be made without placing any tension on the specimen;

D. Lower the weights very slowly to avoid impact loading of the specimen and

E. Observe for any rupture (delamination) at the interface between the spray polyurethane foam and the substrate. Any rupture constitutes a failure of the foam system.

NOTE: Any material that does not pass the adhesion or cohesion test, must be removed, the substrate properly prepared and new material installed.

Cohesion Test

Perform the test as in above except that the bore cut shall be made only through half of the insulation thickness. Observe for any rupture or separation of the specimen. Any rupture constitutes a failure of the foam system. NOTE: Any material that does not pass the adhesion or cohesion test, must be removed, the substrate properly prepared and new material installed.

Verification Of Substrate Preparation

When required by the quality assurance site auditor or the authority having jurisdiction, the preparation of the actual application surface shall be visually verified in three places. The cylindrical cuts shall be made at least 200 mm apart. After the test, the test samples shall be removed, the holes cleaned and refilled with the spray polyurethane foam.

Reporting Requirements

The results of all on site testing shall be recorded on the Daily Work Record.