Fiberglass Line Pipe Sizes & Pressure Ratings: RFQ Reference
When buyers search fiberglass line pipe (and sizes / pressure ratings) before an RFQ, they need a plain map of diameter basis, pressure class language, and which factory data sheet fields to freeze so quotes match — here is the checklist IFGS uses when confirming specs with licensed partner factories.
IFGS is a sourcing and QC partner. We connect buyers to licensed partner factories in China and worldwide, confirm that size and rating fields match the RFQ, compare quotes and run or coordinate pre-shipment QC. IFGS does not own a factory and holds no API license; the license holder is the factory named on its certificate, which you can verify on the API Composite List.
Line pipe vs tubing, casing and spoolable RTP
On this page, fiberglass line pipe means thermoset stick pipe (GRE, FRP, GRP / RTR) used as a flowline or gathering string — not downhole tubing or casing, and not spoolable thermoplastic RTP. Tubing and casing RFQs use different diameter and rating language; spoolable RTP sizing language also differs. Keep those as separate line items. Material context once: GRE pipe, FRP pipe, GRP pipe, RTR pipe, and thermoplastic vs thermoset composite pipe. Category path: line pipe products.
Size fields to freeze before quotes
Buyers searching fiberglass pipe sizes, FRP pipe sizes or fiberglass pipe dimensions often mix OD, ID and nominal-size language in one enquiry. Freeze one size basis per comparable quote line. Values below are field language only — put the project’s own numbers on the RFQ and confirm every figure against the factory data sheet. Do not treat any illustrative range as an IFGS catalog.
| Field | Buyer language examples | What to freeze | Why quotes diverge if missing |
|---|---|---|---|
| Size basis | OD, ID, nominal size, “NPS-style” wording | One primary basis (OD or ID or nominal) plus how the factory drawing names it | One bidder quotes OD, another quotes ID or nominal — apples-to-oranges |
| Wall / pressure-class basis | Wall thickness, pressure class, design class language | Whether wall or pressure class drives the quote, and which document names it | Same “size” with different wall or class looks like a price fight |
| Length / joint length | Stick length, random length, fixed joint length | Joint length family the project accepts (as project-specified) | Freight, joint count and end-prep cost shift when length is vague |
| End finish | Plain end, beveled, joint-ready end for the chosen family | End finish that matches the joint family on the stick-pipe RFQ | End prep and mating hardware get re-quoted after award |
Qualitative only. Confirm OD/ID/wall language on the producing factory’s data sheet and drawing — never invent “standard IFGS sizes.”
Pressure and temperature fields
Fiberglass pipe pressure rating and FRP pipe pressure rating language only works when design pressure, test pressure, temperature and fluid service are named the same way on every bid. Always treat values as project-specified and confirm them on the factory data sheet — never as a generic IFGS table.
- Design pressure — the project’s design pressure wording; confirm the factory data sheet uses the same basis.
- Test / hydrotest language — how the project (and ITP) names test pressure or hydrotest; keep it distinct from design pressure on the RFQ.
- Temperature — operating and design temperature as the project specifies; confirm against the data sheet’s temperature basis.
- Fluid service — fluid family the string will see (as project-specified), so resin system and liner language stay comparable.
Spec family note (once): If an API Spec appears on the project, keep the documents distinct — API Spec 15HR ≠ 15LR ≠ 15S ≠ 17J. Quote against the document your end user names, and confirm the producing factory’s data sheet and certificate scope against that named document. Deep compare (do not rehash here): API 15HR vs 15LR vs 15S buyers guide. IFGS holds no API license; the license holder is whoever the factory certificate names.
What not to invent
- No fake pressure or size tables presented as IFGS standards.
- No “standard IFGS sizes” or “our catalog OD/pressure list.”
- No claim that IFGS holds API 15HR / 15LR / 15S / 17J licenses or any API mark under its own name.
- No mixing thermoset GRE/RTR line-pipe rating language with spoolable RTP / thermoplastic sizing on one comparable quote line.
RFQ checklist for fiberglass line pipe sizes and pressure ratings
Copy into the enquiry:
- Size basis — OD, ID or nominal (one primary basis) plus wall or pressure-class basis as the project names it
- Pressure / temp — design pressure, test/hydrotest language, temperature and fluid service (project-specified; confirm on factory data sheet)
- Spec family — if any (15HR ≠ 15LR ≠ 15S ≠ 17J); name the exact document
- Joint family — freeze once on the stick-pipe string; selector hub: fiberglass pipe joint types compared
- Fittings / flanges — separate line items when needed; fittings buyers guide · flange specification RFQ
- Documents — factory data sheet, drawing, ITP / hydrotest plan, marking vs PO
- Destination — destination, Incoterm and packing
- QC evidence — inspection report, dimensional checks, hydrotest records before release; hold points: pre-shipment inspection checklist
How IFGS works on this order
IFGS first confirms that size basis and pressure/temperature fields match the RFQ. We then compare quotes from licensed partner factories in China and worldwide that produce thermoset fiberglass line pipe in the named Spec family (when cited), check that each factory’s certificate scope matches the project’s named standard, agree the ITP, and run or coordinate pre-shipment QC. IFGS does not run a lab or production line — the producer is the licensed partner factory on the certificate.
See the product range and about IFGS.
Next step
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FAQ
OD vs nominal — what should RFQs freeze?
Freeze one primary size basis per comparable quote line — OD, ID or nominal — and state how the factory drawing names it. Mixing OD language with nominal-size language on the same line is the most common reason fiberglass line pipe quotes diverge before pressure is even discussed.
Can one pressure class cover every diameter?
Not as a blank assumption. Pressure class and diameter interact on the factory data sheet and the project’s design basis. Name design pressure, test language, temperature and fluid for the diameters you actually need, then confirm each line against the producer’s data sheet — do not invent a single class that “covers all sizes.”
How do API Spec families affect rating language?
15HR, 15LR, 15S and 17J are different documents. Rating, test and documentation language must follow the Spec the end user names. Stick-pipe thermoset line pipe is not the same RFQ path as spoolable 15S / RTP. Link the comparison post once above; quote only against the named document and the factory certificate scope.
What should I ask IFGS to confirm before awarding?
Ask IFGS to confirm size basis, pressure/temp fields, Spec family (if any), joint family, documents, destination and QC evidence against the RFQ, then compare quotes from licensed partner factories whose certificate scope matches. Contact sales or start with IFGS AI.