PyroTech logo

PyroCide Clear Technical Data Sheet

PyroCide™ Clear is a two component thin film intumescent coating formulated for existing and new wood structures where the appearance of the wood is important. PyroCide™ Clear will not bubble, haze or crack. It has enough water resistance for interior applications to allow the coating to have an occasional wipe with a damp cloth and maintain its finish.

An intumescent coating is a proprietary formulated blend of compounds which, at ambient temperatures, remain perfectly stable and nonreactive. When the temperature increases, its components undergo a chemical reaction and produce an extended char. This carbonaceous char has a volume many times that of the original thin coating and its low thermal conductivity provides insulation and protects the substrate from the effects of fire propagation.

PyroCide™ Clear

Fire Performance

PyroCide™ Clear provides a Class A flame and smoke rating. It was tested at Underwriters Laboratories to an ASTM E84/UL 723 full scale flame test on red oak (industry standard) at a coverage rate of 180 square feet per gallon. The test results showed a flame spread index of 5 and a smoke density index of 15. A Class A rating requires a flame spread index not exceeding 25 and a maximum smoke density index of 50. The UL test results are available upon request.

PyroCide™ Clear has also been tested on cherry, mahogany, spruce, white ash, white oak and OSB, utilizing small scale tunnel testing. The Class A flame spread results mirror the full scale ASTM E84/UL 723 test.

Physical Properties


Part A: Clear
Part B: Light Tan/Amber

Weight per Gallon

Part A: 10.5 lbs./gallon
Part B: 11.7 lbs./gallon

Shelf Life

12 months stored in unopened containers between 40 degrees and 90 degrees Fahrenheit

Unit Size

1 Gallon — 2, 2.5 liter Jerri cans
5 Gallon — 2, 2.5 gallon Jerri cans
Consult SDS for further details

Product Use


Before proceeding, please read the following information carefully to ensure that the correct application procedure is understood fully.

All surfaces to be coated should be clean, dry and free from oil, grease or other contamination. Softwoods require no additional preparation. Hardwoods should be lightly abraded and all residue should be removed. For application of stain prior to applying PyroCide™ Clear, the stain must be 100% dry as any water/solvent retained may become trapped under the PyroCide™ Clear and cause bubbling. If coating any surface other than raw substrate, an adhesion test on a small sample should be performed first.


PyroCide™ Clear is mixed as a 1 to 1 ratio with equal parts of A and B by volume, (not weight). Do not mix more than can be applied in 30 to 45 minutes.
While mixing you may notice a slight exothermic reaction (warming). This is a normal hydrogen reaction and does not affect the cure time.

If applying by brush or to lower viscosity for spraying, you may add UP TO 10% water by volume to reduce brush drag. If you do reduce with water do not add the water to your spread rate. Adding 10% water DOES NOT increase your coverage from 180 square feet per gallon to 198 square feet per gallon.


PyroCide™ Clear may be sprayed or brushed on to give a smooth, hard uniform film. While one coat may be applied to horizontal surfaces, vertical surfaces require two coats to avoid runs and sagging. Generally three hours is required between coats to allow the first coat to become dry to the touch before applying the second coat.

Apply PyroCide™ Clear at a coverage rate of 360 square feet per gallon or 14.63 grams per square foot wet weight per coat when applying two coats. Apply at 180 square feet per gallon or 29.25 grams per square foot wet weight when applying one coat. These spread rates will provide the required amounts to pass the ASTM E84/UL 723 (with results similar to our UL flame and smoke test ratings). Other tests requirements may require an adjustment either up or down in the application rate. Consult with our PyroTech staff if other test requirements need to be met.

Drying times will vary according to ambient conditions. High humidity and/or low temperatures will increase drying time significantly. PyroCide™ Clear will achieve a partial cure after 24 hours and may be handled and topcoated with a solvent based varnish. A full cure will not occur for seven to 10 days. During this time, without a topcoat, PyroCide™ Clear is still soft and may be scratched or fingerprints may remain in the film if not handled carefully. Oven curing at 100 degrees F or 40 degrees C will decrease cure times. Exceeding these temperatures will cure PyroCide™ Clear too fast, resulting in bubbles in the emulsion.

Application to previously finished surfaces

Because of the wide variety of finish materials, it is necessary to test PyroCide™ Clear on small samples of the finished substrate to ensure proper adhesion and finish. The previous finish must be sanded and the dust, oils, grease and other contaminants removed before applying PyroCide™ Clear.

Top Coating

DO NOT USE WATERBORNE VARNISHES prior to contacting PyroTech. Testing is ongoing with these finish systems. Most waterborne varnishes have shown to be incompatible with PyroCide™ Clear.

Allow 24-hour cure of PyroCide™ Clear before applying a solvent-based topcoat.

PyroCide™ Clear does not need to be sanded before applying a topcoat. However a light sanding with 220 grit sandpaper may be applied to smooth before top coating. Use caution when sanding. Wear a NOS approved dust mask as the dust is slightly acidic and may cause sinus irritation. Heavy sanding will result in removing too much flame retardant and will require recoating to bring the coating back to the proper levels.

In hot or cold areas and/or in areas where humidity is consistently 70% or higher a topcoat will be required as the coating will soften, dry out and the finish will be diminished. In these high humidity areas, sealing the substrate prior to applying PyroCide™ Clear is also recommended. As with stains, an adhesion test is recommended for the particular sealer used. High touch/traffic areas will also require a topcoat. Top coating provides sheen level adjustment to PyroCide™ Clear's high-gloss natural state. A polyurethane coating, such as Varathane, or acid cure varnishes provide a good general purpose option where the substrate is being used on wood clad walls and framing. For wearing surfaces like furniture you should use a two pack acid cure varnish for maximum protection. Pure Acrylics, short oil alkyds or silicon alkyds should NOT be used as topcoats.

Page Last Edited: Monday, March 29, 2021

Search this site

What's New or Important?