GB2171105A

GB2171105A - Intumescent fire retardant composition

Info

Publication number: GB2171105A
Application number: GB08601744A
Authority: GB
Inventors: Thomas William Palmer
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-01-24
Filing date: 1986-01-24
Publication date: 1986-08-20
Also published as: JPS61275387A; GB8601744D0

Abstract

A fire retardant material comprises an intumescent fire retardant, such as a two component fire retardant epoxy resin, and a plurality of undulating spheroids. The spheroids may occupy about 50% by volume of the layer. A second layer comprising fire retardant epoxy resin may be applied over a first layer. The inclusion of spheroids in the fire retardant material substantially increases the time which it takes for the substrate to reach 93 DEG C and hence gives additional time for motor operated safety valves and the like (which become unreliable in operation above 93 DEG C) to function properly.

Description

SPECIFICATION Fire retardant material and process for applying same to a substrate This invention relates to a fire retardant material and to a process for applying said fire retardant material to a substrate.

Hydrocarbon fires in petroleum refineries and chemical plants develop extremely rapidly and generate intense heat, for example in excess of 1100 C in less than five minutes.

Above 93"C (200"F) many safety devices such as motor-operated valves will notfunction properly and hence it is essential to provide some form of insulation which will prevent the safety devices fron becoming too hot too quickly.

U.S. Patents 4,307,813 and 4,414,251 are directed to fire retardant enclosures and materialsforproviding fire protection in the ambient to 93"C temperature range for sufficient time to permit safety devices and valves two be operated properly.

Fire-retardant coatings are known which comprise a fire-retardant substance which intumesces (i.e. swells up) when exposed to high temperatures to form an exterior ceramic-like char. This intumescence does not start until the temperature reaches about 1 99"C (390"F). One example of such a fire retardantsubstance is a two-component epoxy resin coating sold underthetrade mark PITT-CHAR which is a commercially available product of Pittsburgh Paints.

PITT-CHAR (trademark) isthefirstand only fire retardant coating to meetthestandardsofUnderwri- ters' Laboratories Bulletin 1709 ("UL1709"). UL 1709 provides fortesting under conditions similarto those encountered in a hydrocarbon fire. PITT-CHAR (trademark) received a one hour rating for steel protection when applied, by spraying, to a thickness of 9.1 mm (0.36 inch).

The aim at least preferred embodiments of the present invention is to provide a fire retardant material which, on the one hand will intumesce and, on the other, will reduce the rate at which the substrate to which the material is applied will reach 93"C.

According to the present invention there is provided a fire retardant material which comprises a fire retardant substance which intumescesata certain temperature and a plurality of insulating spheroids.

Preferably, the fire retardant substance comprises a two component epoxy resin.

Advantageously, the diameter of said spheroids lies in the range of from 30 to 300 microns.

Preferably, the spheroids occupy from 30% to 75% by volume of the total volume of said fire retardant material.

Advantageously, the spheroids are composed of one or more of the following materials, phenolic resin, sodium borosiiicate glass, free-flowing powder insoluble glass, ceramic and silica.

The present invention includes both the homogenious inclusion ofthe spheroids in the fire retardant substance and the selective addition to the fire retardant substance to provide at least one layer of said fire retardant substance alone, and at least one layer comprising a mixture of said fire retardant substance and said insulating spheroids.

The present invention also provides a substrate provided with a coating offire retardant material in accordance with the present invention. In embodi ments where at least one layer comprises fire retar dantsubstance alone and anotherlayercomprises a mixture of fire retardant substance and insulating spheroids the layer comprising the mixture offire retardant substance and insulating spheroids is preferably disposed closer to the substrate than the layer comprising fire retardant substance alone.

The present invention also provides a process for applying a fire retardant material in accordance with the invention to a substrate which process comprises the steps of applying a fire retardant substance which intumesces at a certain temperature and a plurality of insulating spheroids to said substrate.

Preferably, the fire retardant substance comprises a two component epoxy resin.

Advantageously,thefire retardant substance and said insulating spheroids are sprayed onto said substrate.

The fire retardant substance and the insulating spheroids may be sprayed from a single source comprising fire retardant substance with insulating spheroids therein. Alternatively the fire retardant substance and the insulating spheroids are provided from separate and distinctsources. Preferably the fire retardant substance and said insulating spheroids are supplied to the head of a spray nozzle priorto being sprayed onto said substrate.

If desired the insulating spheroids are withheld from said spray nozzle for a certain period of time so as to provide a layer of saidfire resistance substancefree from said insulating spheroids.

Preferably, the diameter of said spheroids lies in the range of from 30 to 300 microns.

Advantageously, said spheroids occupy from 30% to 75% byvolume ofthe total volume of said fire retardant material.

For a better understanding of the invention reference will now be made, by way of example, to the accompanying example.

EXAMPLE 10.7 litres of PITT-CHAR type A was mixed with 8.2 litres of PITT-CHAR type B and thinned with 3 litres of methylene chloride to form 21.9 litres of liquid PITT-CHAR fire retardant epoxy resin ready for spraying. The mixture was placed in a container maintained at between 16 and 27"C.

4.5 kg of Union Carbide MICROBALLOONS (Trademark) spheroids having an average diameter of 80 microns (range 44-175 microns) were placed in a second container.

Two tubes led from the first and second containers respectively to spray nozzle having separate and distinct outlets forthe PITT-CHAR and the spheroids.

The PITT-CHAR was supplied to the spray nozzle at a pressure of 11.60 barA and the MICROBALLOONS were urged towards the spray nozzle by compressed air at 5.80 barA.

The spray nozzle was pointed towards a substrate of steel sheet and was activated until a layer approximat ley6mmthickwasformed.Thislayerwasfoundto comprise 50% (by volume) spheroids.

The supply of spheroids was then isolated from the spray nozzle and a further 6 mm of PITT-CHAR applied.

The prepared substrate and a substrate coated with 12 mm PITT-CHAR alone were then exposed to a source of heat at 1 094"C. It was found that the substrate coated with 12 mm of PITT-CHAR alone reached 93"C in 900 seconds. In comparison the substrate prepared in accordance with the example did not reach 93 C for 1620 secondsthereby exhibiting a quite remarkable improvement.

Various modifications to the Example described are currently envisaged, for example the substrate could be covered with different layers of fire retardant material containing different proportions of spheroids. Furthermore, the mean diameter ofthe spheroids could conceivably be varied frbm layer to layer.

The fire retardant substance may be mixed prior to use or could be mixed in the spray nozzle. Alternative ly, the components of the PITT-CHAR could be supplied through totally separate and distinct orifices in the spray nozzle, the mixing ofthe components occurring on the substrate itself.

Claims

1. Afire retardant material which comprises a fire retardant substance which intumesces at a certain temperature and a plurality of insulating spheroids.

2. Afire retardant material as claimed in Claim 1, wherein the said fire retardant substance comprises a two component epoxy resin.

3. Afire retardant material as claimed in Claim 1 or 2, wherein the diameter of said spheroids lies in the range of from 30 to 300 microns.

4. Afire retardant material as claimed in any preceding claim wherein said spheroids occupy from 30% to 75% by volume of the total volume of said fire retardant material.

5. Afire retardant material as claimed in any preceding claim wherein said spheroids are composed of one or more ofthefollowing materials, phenolic resin, sodium borosilicate glass, free-flowing powder insoluble glass, ceramic and silica.

6. Afire retardant material as claimed in any preceding claim which comprises at least one layer of said fire retardant substance alone, and at least one layer comprising a mixtureofsaidfireretardant substance and said insulating spheroids.

7. Asubstrate provided with a coating of fire retardant material as claimed in any preceding claim.

8. Asubstrate as claimed in Claim 7 when appended to Claim 6, wherein said layer comprising a mixture of said fire retardant substance and said insulating spheroids is disposed closerto said substrate than said layer of said fire retardant substance alone.

9. A process for applying a fire retardant material as claimed in Claim 1 to a substrate which process comprises the steps of applying a fire retardant substance which intumesces ata certain temperature and a plurality of insulating spheroids to said substrate.

10. A process according to Claim 9, wherein said fire retardant substance comprises a two component epoxy resin.

11. A process according to Claim or 10, wherein said fire retardant substance and said insulating spheroids are sprayed onto said substrate.

12. A process according to Claim 11, wherein said fire retardantsubstance and said insulating spheroids are supplied to the head of a spray noule priorto being sprayed onto said substrate.

13. A process according to Claim 11, wherein said insulating spheroids are withheld from said spray nozzle fora certain period of time so as to provide a layer of said fire resistance substance free from said insulating spheroids.

14. A process according to any one of Claims 9 to 12, wherein the diameter of said spheroids lies in the range of from 30 to 300 microns.

15. A process according to any one of Claims 9 to 14, wherein said spheroids occupy from 30% to 75% by volume of the total volume of said fire retardant material.

16. A process according to any one of Claims 9 to 15, wherein said spheroids are composed of one or more ofthefollowing materials: phenolic resin, sodium borosilicate glass, free-flowing powder insoluble glass, ceramic and silica.

17. A fire retardant material substantially as hereir described.

18. A process for applying a fire retardant material as claimed in Claim 1 to a substrate substantially as herein described.