The aim of this work has been to provide documentation of importance for tile application of glass fibre reinforced plastics (GRP) pipes on topside offshore oil installations. The paper is comprised of summaries of review reports (1), (2) of available literature, technical reports etc. together with our own investigations. The results illustrate that glass fibre reinforced plastics represent a cost effective material for offshore sea water pipe systems, especially with respect to low weight and corrosion resistance. Fire test results also indicate that GRP represents a safe choice of materials for the applications which have been studied.
The need of the oil companies to continuously seek more cost-effective and safer materials for offshore installations and of the suppliers to find new markets were the driving forces that initiated this work. Glass fibre reinforced plastics (GRP) are materials which, mainly due to low weight and corrosion resistance, are attractive alternatives to many metals. The GRP materials studied in this work are the thermoset matrix materials; polyester, vinylester, and epoxy resins reinforced with glass fibres.
GRP is not a new material in the offshore oil industry. In fact, it represents a proven technology. The list of applications on world wide offshore installations include a variety of products, e.g. sea water pipe systems, water injection pipe and tubing, storage tanks, casings, J-tubes, corrosion protection, life boats, housing and shelters, cable ladders and trays etc.
Sea water pipe systems represent the dominant application of GRP offshore. Between 60 and 90 installations have been identified by the project group. Ballast water and cooling water systems are the most frequent of these. Four examples have been registered where GRP pipes have been used in offshore fire water systems. This is a particularly demanding application, where so far most experience has come from the much larger number of installations onshore (in oil refineries, chemical plants etc.
Even though there are many examples of offshore applications of GRP, a more extensive use could have been expected due to the advantages offered by the materials. There are several reasons for the relatively limited application of GRP up to now. The rules and regulations that apply to offshore installations are not adapted to new materials and are generally conservative and restrictive. This is especially the case in areas such as the North Sea. There is a lack of standardization, specifications and relevant documentation (particularly on fire properties and long term properties). The concern about fire hazards is a major factor that prevents a more extensive use. Limited competence and confidence in the materials are also restraining factors.
The present paper concentrates on five items:
The performance of GRP pipes in fire situations based on a review of thirteen independent fire test programs (performed mainly in Europe) and to some extent on fire testing carried out by the project group and reported here for the first time.
