Fiberglass Pipe for Dry Deluge and Confined Space Service
Authors: Folkers Joie L. 
Published: October 2008

Fiberglass piping has typically been prohibited from use in dry deluge fire protection systems and in confined spaces for reasons of flammability, smoke density and toxicity. Advanced resin technology has emerged which breaks through these barriers. The .light weight, corrosion resistance and low maintenance advantages offiberglass pipe can now be joined by features such as zero flame spread, temperature and weather resistance and low smoke density and toxicity to provide a solution to a broader range of offshore piping needs. These needs include critical service such as fire protection. Available in products designed for both normally wet and normally dry conditions, polysiloxane-modified phenolic piping can be used even in systems potentially exposed to jet fire. This paper reviews the designs and test results, obtained from independent third-party laboratories, of products developed from this novel technology.

Introduction

The use of composite materials on offshore platforms is increasing and becoming more commonplace. The intrinsic properties of composites, namely light weight and corrosion resistance, make them very attractive when a life cycle cost is considered vs. carbon steel. Cost advantage is seen even in purchase price when compared to many alloy metals. In many deepwater applications, composites may be the only possible answer.

Polysiloxane-Modified Phenolic

The strength and fire properties of phenolic resin have made it an attractive material for use in the matrix of composites. On the negative side, phenolics are historically difficult to process, brittle and have poor adhesion properties.1 A means of modifying the base phenolic material has been developed which addresses each of the above negative features while not diminishing, and in some cases even enhancing, the positive aspects of the material. This modification, done with polysiloxane, reduces the water content of the resin (making it easier to process), provides flexibility (making it more impact resistant) and dramatically increases the shear strength of adhesive bonding of the material (Table 1). 2 Initial studies have shown a possible increase in the chemical resistance of the resin after the polysiloxane modification (Table 2)3 and a reduction in toxicity - which was already very low (Table 3).4,5,6

Deluge Piping

For reasons of weight and, for other materials, corrosion resistance to sea water, fire protection systems on offshore platforms are often designed to have unfilled, or dry, sections. Most common is the practice to have a pressurized ring main around the perimeter of the platform, filled with water, with branches coming off the main through valves to the distribution or sprinkler piping. The valves are designed and the control system set to quickly open in the event a fire is detected. The distribution piping, normally empty, is then flooded with water. Open nozzles are located throughout the piping network to disperse water to extinguish the fire or provide safe egress passages from the fire affected area. FRP pipe has historically been restricted from use in this deluge application due to its flammability. Advances in resin technology and fire endurance performance in regulated testing are causing composites to get a fresh look.