Why the BOQ matters more than the supplier
A supplier can only quote what you tell them. The difference between two offers for the same project sometimes reaches thirty to forty percent — because one supplier quoted the exact schedule, standard and material, and the other guessed. On welded line pipe connections especially, there is no "close enough": the fittings, flanges, gaskets and bolts must inter-match or the joint will not be made to code. Your list is the contract between your project and everyone who bids on it.
Start with the project frame
Before the line items, give the reader the frame: project or plant name, the duty line, the relevant code or class (e.g. ANSI/ASME B16.5 Class 600), the quantities of connections involved, and the delivery target and location. This lets suppliers align their material to the same design pressure — and lets you compare like for like.
The anatomy of a line item — remove the guesswork
Each row of the BOQ should say:
- Item number / tag — so you can reference it on the drawing
- Item type — fitting, flange, gasket, bolt set, stopper
- Standard — e.g. ANSI/ASME B16.5, ASME B16.20, ANSI B16.9
- Material grade — e.g. ASTM A105, ASTM A193 Gr. B7
- Schedule / class — e.g. Sch. STD, Class 600
- Size, dimensions and any ends — e.g. 12" × 12" × 8"
- Quantity and unit — pcs, sets, meter
- Certificates, testing, coating notes
Write the line like a sentence: example
Take a vague note and the same line rewritten so a quoting team reads it without a single guess:
ITEM A-14 · Weld neck flange · NPS 8, Class 600, RF · ASME B16.5 · material ASTM A105 · Sch. STD bore · EN 10204 3.1 · 12 pcs · gaskets 4 pcs spiral wound graphite filler, ASME B16.20 · stud bolts A193 Gr. B7 × A194 2H nuts, 5/8" × 3-1/2", 24 sets.
That one line tells the factory everything about price: the standard, the material, the class, the quantities and the bolt set. In practice, the three fields that cause most re-manufacturing are the facing (RF vs FF), the schedule on the bore, and the matching bolt set — which is why we always quote flanges, gaskets and bolts as one set.
Common mistakes that delay quotes
- Generic lines like "pipe fittings" — a real price is impossible
- No standard or class — suppliers guess differently
- Mixing the flange class but forgetting the gasket
- No schedule — STD vs Sch. 80 changes the whole price
- Not stating whether ends are beveled, threaded, or socket
- Missing the certificate requirement — Type 3.1 required or not
- No delivery location or Incoterm — prices cannot be compared
Do you have a list already but no time to clean it into this format? That is exactly the work we do — send us the raw file (Excel, PDF or Word) through the RFQ page and we will structure, review the spec against the standards, and return a consolidated, comparable offer.
Frequently asked questions
What is a bill of quantities (BOQ) in procurement?
A bill of quantities is a line-by-line list of the equipment, materials or parts a project needs, with enough detail — size, standard, material, schedule/class, quantity and certification — for a supplier to price it accurately without guessing.
What is the single biggest cause of wrong quotes on a BOQ?
Missing the standard and class on a line item. A generic line like "pipe fittings" or a flange with no pressure class forces every supplier to guess differently, which is why the resulting quotes are impossible to compare like for like.
Should flanges, gaskets and bolts be listed as separate line items?
They can be, but they should always be specified together as a matched set — same pressure class, compatible facing and a gasket/bolt combination suited to the service — because they form one bolted connection, not three independent parts.
