Burn Barrier BB6-3


BURN BARRIER™ 6-3 is a clear and colorless surface impregnation for application on interior surfaces of unpainted wood and plywood



BURN BARRIER™ 6-3 is a clear and colorless surface impregnation for application on interior surfaces of unpainted wood and plywood to reduce flame spread and smoke when exposed to fire. BURN BARRIER™ 6-3 does not contain Halogen or Sulphur compounds (Chlorine less than 0.005% by weight; Sulphur less than 0.020% by weight).


Surface impregnation by spraying allows BURN BARRIER 6-3 to penetrate into the
surface of the wood. Application shall be with convention allow pressure, airless, or orchard type sprayer. Spray uniformly over the entire surface using a coarse nozzle. Cover all metal surfaces before spraying.

Apply two coats of BURN BARRIER 6-3, each coat at 200 square feet per gallon. Allow at least 24 hours drying time between coats. Proper drying conditions of temperature and humidity are necessary. Treated surfaces may be left unfinished, stained, painted or coated with varnish or lacquer. If any residue appears on the surface, sand and wipe clean before applying finish coat. Equipment should be cleaned with water. Before finish system is applied, moisture content of flame retarded wood must not exceed 12% and must be stabilized at least four days.

Recommendations for coatings to be applied over BURN BARRIER™ 6-3 are: Cabot, Cuprinol, and Olympic Stains; Varnishes – One coat Fuller’s penetrating wood-finish followed with two coats Fuller’s all-clear varnish, Gloss, Semi-gloss, or Flat. Prattand Lambert’s Varnish system may be used as follows; one coat of Pale 38 Trim Gloss followed with two coats of Pale 38 Trim Gloss, Semi-gloss or Flat.

If recommended coating system is not used, the user is responsible to see that an appropriate test is made of the proposed finish system by an independent testing laboratory.
The ASTN E84-80 Fire Hazard Classification for BURN BARRIER™ 6-3 is as follows; Flame Spread – 25, Smoke Density – 5


BURN BARRIER™ 6-3 is a clear, colorless fire retardant coating. The coating is impregnated into bare, uncoated wood by spraying.Two spray coats are required, each coat at 200 sq. ft. per gallon with at least 24 hours drying in between coats. Good drying condition is a must during spraying. Application by spraying shall be with either conventional low pressure, airless, or orchard type paint spray equipment. Spray uniformly over the entire surface, using a coarse nozzle. Hold spray gun about two feet from material. Apply enough coating to make material thoroughly wet.. Spray equipment is rinsed with water after use. 6-3 treated wood may be stained or varnished. An Oil Base stain should be used and a varnish over it such as Fuller’s All-clear, gloss. Stain and fill, as required.

One coat Dupont’s Penetrating Wood Finish Two coats DuPont’s Clear Gloss Varnish, Interior.
One coat Fuller’s All-Clear Varnish, gloss Two coats Fuller’s All-Clear Varnish, gloss,
semi-gloss or flat.

First coat: Pratt and Lambert’s Pale “38” Trim Gloss Second coat: Pratt and Lambert’s Pale “38” Trim Gloss Third coat: Pratt and Lambert’s Pale “38” Trim Gloss, Dull or flat.

First coat fibbed Second coat of varnish sanded as required Finish coat; no additional

Weatherproof paint may be applied over wood treated with 6-3.

Over wood treated with 6-3
Rezite XX
Cabot Shingle Stain #230
The clear exterior top coat has to be renewed after approximately 2 years in order to protect
6-3 from being leached out by exposure to rain.
LACQUER SYSTEMS suggested for use over 6-3 treated wood:
Stain and fill as required
First coat: Fuller’s Synlac Penetrating Base Coat 7743
Second coat: Fuller’s Synlac Sanding Sealer 7782
Third coat: Fuller’s Synlac Sanding 7782
Fourth coat: Fuller’s Synlac Clear Flat 7781 or 7700
Clear Gloss
(For thinning, use Fuller’s Synlac Thinner)
Fire coat nibbed
Second and third coats of lacquer sanded as required
Finish coat: Polish as required
First coat: DuPont’s Penetrating Primer No. 1362
Second coat: DuPont’s Sanding Sealer No. 1999
Third coat: DuPont’s Sanding Sealer No. 1999
Fourth coat: DuPont’s Clear Gloss No. 1655, or
Clear Semigloss No. 1541 or Clear Flat No. 1672
(For thinning, use DuPont’s No. 3661)
First coat fibbed
Second and third coats as required
Finish coats no additional treatment

Test Specimen Flame Spread Fuel Smoke
E 84-80 Contribution Density
25 25 5
Douglas Fir
Applied 2 coats each
at 200 sq. ft. per gallon

Note: Cover all metal surfaces before spraying.

Approved: City of Los Angeles
Information provided herein is based on tests believed to be reliable. Inasmuch as Fire
Retardants Inc. has no control over the use or application to which others may put this material,
we make no guarantee or warranty. Our products are sold on the condition that each user of the
material make their own evaluation to determine the material’s suitability for their own particular
NOTE: All porous surfaces should be properly sealed before applying fire retardant paint or
CAUTION: It is recommended that a test application be completed prior to end use.

Additional information

Weight 10 lbs
Dimensions 12 × 12 × 12 in


Product Spec Sheet
Click Here to be Emailed Material Safety Data Sheet (MSDS)
Test Data Sheet
Fire Test