Technical Reference

Flange P-T Ratings — ASME B16.5

Maximum allowable working pressure (bar g) for raised-face flanges. Values vary by material group — Group 1.1 (A105, A181, A350 LF2) and Group 2.1 (A182 F316, F304) shown.

Group 1.1 — Carbon Steel (A105, A350 LF2)

Group 2.1 — Austenitic Stainless (A182 F316, F304)

Source: ASME B16.5-2017, Tables 2-1.1 and 2-3.1. Values in bar(g). For RTJ flanges, ratings are identical to RF. For full-face flanges mated with flat-face flanges, consult the standard for restrictions.

Butt-Weld Fittings — ASME B16.9

Centre-to-face (C-F) and end-to-end dimensions (mm). LR = Long Radius (1.5D), SR = Short Radius (1.0D). Always default to LR elbows unless specifically required otherwise.

Source: ASME B16.9-2018. All dimensions in mm. A = 90° LR elbow C-F, B = 90° SR elbow C-F, C = 45° elbow C-F, U = 180° return C-C, M = equal tee C-F, E-E = end-to-end (reducers and caps).

Socket-Weld & Threaded Fittings — ASME B16.11

Centre-to-face (C-F) and end-to-end (E-E) dimensions (mm) for Class 3000 and Class 6000. Socket-weld fittings are limited to NPS 4 maximum per B16.11.

Source: ASME B16.11-2021. C-F = Centre-to-Face (mm). E-E = End-to-End (mm). Class 3000 SW = approx. Sch 80 bore. Class 6000 SW = approx. Sch 160 bore. Threaded fittings same dimensions, Class 2000/3000/6000.

Stud Bolt Lengths — ASME B16.5 Raised Face

Stud bolt lengths (mm) including two heavy hex nuts for raised-face flanges. Bolt diameter (Ø) shown per class/size. Add ~3mm for RTJ flanges.

Source: ASME B16.5-2017, Appendix E. L = stud bolt length (mm) including 2 heavy hex nuts. Ø = nominal bolt diameter. Add ~3mm for RTJ flanges. Class 1500 and 2500 not available for NPS 14 and above in B16.5 — refer to ASME B16.47 for large diameter flanges.

Pipe Weight — Carbon Steel (kg/m)

Weight per metre for carbon steel pipe (density 7850 kg/m³). Useful for support design, hydrotest calculations, and structural loading. Water weight shown separately for hydrotest.

Steel density 7850 kg/m³. Water density 1000 kg/m³. Total hydrotest = pipe weight + water weight. For insulated lines, add insulation weight (typically 5–15 kg/m depending on thickness and material). Always verify with your stress engineer’s model.

Conversion Tables

Common unit conversions for piping design. Pressure, temperature, length, force and flow.

NPS to Metric (mm)

Pressure Conversions

Temperature Conversions (°C ↔ °F)

Formula: °F = (°C × 9/5) + 32. Formula: °C = (°F − 32) × 5/9. 1 bar = 100 kPa = 0.1 MPa = 14.5038 psi.

Insulation Thickness — Standard Reference

Typical insulation thicknesses (mm) for process piping by service temperature and pipe size. Values are indicative — always verify against your project insulation specification.

Typical values for mineral wool / calcium silicate insulation. Cold insulation typically cellular glass or elastomeric foam. Always verify against project insulation spec — owner specifications frequently override these standard values. Add insulation thickness to pipe OD when checking clearances in 3D model.

Insulation Impact on Clearances

Min C-C = minimum centre-to-centre spacing between two pipes of equal size with equal insulation, with 25mm clearance between insulation surfaces. Always check insulation clearances in 3D model with insulation layer turned ON before issuing for construction.

Olet Dimensions — MSS SP-97

Branch outlet fittings: Weldolet (butt-weld), Sockolet (socket-weld), Threadolet (threaded), Elbolet (elbow branch). Use olet when branch < 50% of header size; use tee when branch ≥ 50% of header. Dimensions in mm.

Weldolet — Run Pipe OD × Branch Size

Sockolet & Threadolet — Height (mm)

Source: MSS SP-97. Heights are approximate — verify with manufacturer data sheets for exact dimensions. Weldolet height = distance from run pipe centreline to top of fitting. Sockolet and Threadolet heights from run pipe OD surface.

Valve Face-to-Face Dimensions — ASME B16.10

Face-to-face (F-F) dimensions (mm) for flanged valves. Critical for isometric dimensioning and spool fabrication. Class 150 and 300 shown — higher classes are shorter in some valve types.

Gate Valves — Flanged RF

Globe & Check Valves — Class 150/300 (mm)

Source: ASME B16.10-2009. All dimensions in mm, flanged raised-face ends. Butterfly valve F-F dimensions per API 609. Control valve F-F varies by manufacturer — always verify with vendor data sheet before finalising isometric.

Pipe Support Types — MSS SP-58

Standard pipe support types as defined by MSS SP-58. These type numbers are referenced universally in stress reports and piping specifications. Know these cold.

Source: MSS SP-58 & MSS SP-69. Types 51 and 52 require spring design by stress engineer. Type 54 (anchor) transfers all forces to structure — verify structural capacity before specifying. Types 37/38 are most common for guides; Type 54 for anchors. Highlighted types are the ones you will encounter on 90% of projects.

Gasket Dimensions — ASME B16.20 / B16.21

Gasket dimensions (mm) for raised-face (RF) and ring-type joint (RTJ) flanges per ASME B16.21 (non-metallic) and B16.20 (metallic). A gasket is single-use — never reuse a gasket.

Raised-Face Spiral-Wound Gaskets — B16.20 (mm)

RTJ Ring Gaskets — B16.20 Ring Numbers

Source: ASME B16.20-2017, B16.21-2016. Spiral wound gaskets: verify inner ring and outer ring requirements per service. RTJ rings: R = oval cross-section (standard), RX = pressure-energised, BX = high-pressure API 6BX service. Always specify ring number on isometric.

Branch Reinforcement — ASME B31.3 Para 304.3

Quick reference for branch connection reinforcement requirements. When is a reinforcing pad required? Use this table as a first check — always confirm with stress engineer for critical services.

Tee vs Olet Selection Guide

Required Reinforcement Area — B31.3 Simplified

Source: ASME B31.3-2020, Para 304.3. These are guidance values only — actual reinforcement requirement depends on design pressure, temperature, material, and exact wall thicknesses. Always perform the B31.3 area replacement calculation or use your stress engineer’s judgment. A Weldolet or integrally reinforced tee is always preferable to a pad for high-pressure, high-temperature, or cyclic service.

Hydrotest Pressure — ASME B31.3

Minimum hydrotest pressure = 1.5 × Design Pressure × (Allowable stress at test temp / Allowable stress at design temp). Pneumatic test = 1.1 × DP. Maximum test pressure limited by yield strength.

Hydrotest Pressure by Flange Class — A105 Carbon Steel

Test Blind Thickness (Temporary Blinds) — Guidance

Blind thicknesses are guidance values for full-face contact blinds at test pressure. Always calculate per ASME VIII Div.1 UG-34 or B31.3 para 345. Verify material yield strength. Add corrosion allowance for reusable blinds. Hydrotest temperature must be at least 17°C above the nil-ductility transition temperature of the material.

Allowable Nozzle Loads — API 610 / API 617 / NEMA SM23

Maximum allowable forces and moments on equipment nozzles. These are the limits your piping stress analysis must satisfy. Values shown are typical — always verify against vendor datasheet which may differ significantly.

Centrifugal Pumps — API 610 (12th Ed.) Table 4

Steam Turbines — NEMA SM23 (Guidance Values)

Source: API 610 12th Ed. Table 4, NEMA SM23. These are minimum values — some vendors impose stricter limits, especially for high-speed or high-temperature machines. Always obtain vendor-specific allowables at project start. API 617 (centrifugal compressors) uses similar format — request Table 1 from vendor. Nozzle load compliance is mandatory — exceeding limits can void equipment warranty and cause seal failures.