Barred Tees for Piggable Pipelines

A barred tee is a run / branch tee fitted with internal guide bars across the branch opening, intended to keep pigs, scrapers and inspection tools travelling on the run rather than dropping into the branch. The bars are a pig-guidance feature; they are separate from the fitting’s pressure-boundary reinforcement, and their design is specific to the pipeline and tool.

No. The bars are intended to guide compatible tools, but passage depends on the approved bar design and the specific tool — cleaning pigs, scrapers, gauging pigs and in-line inspection tools have different envelopes, discs / cups, sensors and articulation. Size and type alone are not sufficient; compatibility is confirmed against the approved design and, where required, a passage trial for that tool.

From an approved cross-section drawing that fixes bar count, section shape, width / thickness, clear spacing, orientation to flow, edge radii, run-bore contour and attachment weld detail — set by the pipeline and tool requirements. There is no single universal spacing formula for all pigs and branch sizes.

The tee body follows ASME B16.9 for dimensions, or MSS SP-75 for high-yield (WPHY) wrought pipeline fittings, with ASME B16.25 end preparation. SP-75 is a high-strength wrought-fitting standard, not a material standard for stainless, nickel or titanium. The bar assembly is qualified separately to the approved design and the purchaser / tool requirements; editions are fixed by the order.

Per finished barred tee, from the BOM or CAD model — the tee body plus the actual guide-bar and attachment-weld mass, adjusted for final machining. A bare-tee weight or a straight-pipe formula does not represent the finished barred tee, and there is no single exact weight for all bar designs at the same NPS and schedule.

Bars occupy part of the branch opening and can affect branch flow, debris collection and cleaning, so we quote the open-flow area and any hydraulic assessment where specified rather than claiming zero pressure loss. Restrictions on inspecting, repairing or replacing bars are stated with the design.

Provide run and branch NPS and wall, equal or reducing configuration, body and bar materials, standard editions, design / service conditions, the pig / tool details and flow direction(s), the bar drawing where available, and the required inspection and documentation package. Availability by material, size and design is confirmed with the quotation.