Pump MAWP & Material Check (API 610)

Project

Requisition / PO reference

Revision

Margin basis for the required MAWP Sec. 6.3.5 applies the margin to the differential pressure

Temperature for the Sec. 6.3.5 rating floor 6.3.5 a) states no temperature; 38 °C is the alternative reading

Severity of the rating-floor check Sec. 6.3.5 is a “shall”; downgrade only against an agreed deviation

Input field Calculated output Derived from the material class Everything runs in your browser — nothing is uploaded. The register is remembered by this browser only, until you press Clear.

1Pump Identification & Configuration

The pump type sets which pressure-rating floor of Sec. 6.3.5 applies. The material class sets the casing material, and with it the ASME B16.5 material group used for the flange-rating floor.

Pump tag

Vendor model

P&ID number

Mounted on / vessel

API 610 pump type —

Seal plan (API 682)

Installed pressure transmitter

Casing joint Axially split invokes the 6.3.5 a) floor for any type

API 610 material class (Table H.1) —

Flange pressure class for the floor Sec. 6.3.5 a) floor is the Class 150 (PN 20) rating

ASME B16.5 material group —

2Pressure & Temperature Inputs

All pressures are gauge. Enter the head and relative density on the basis you intend to hold the vendor to — Sec. 6.3.2 lets the purchaser escalate the maximum discharge pressure for maximum relative density, maximum impeller and trip speed. Record which of those the entered values represent.

Basis of the maximum differential pressure

H_max — Head at the impeller and speed considered m Shut-off head is the usual basis

SG_max — Relative density considered Sec. 6.3.1 uses normal SG; 6.3.2 a) allows maximum

P_s,max — Maximum suction pressure barg Sec. 3.26, non-transient

Sec. 6.3.2 a) maximum specified relative density Sec. 6.3.2 b) maximum impeller diameter / stages Sec. 6.3.2 c) operation to trip speed

Temperatures

Maximum pumping temperature °C Sec. 3.24, including upset conditions

Casing design temperature °C

Temperature basis of the vendor MAWP °C Sec. 6.13.2 j) — a nameplate item

Stated MAWP and competing pressure demands

(A) MAWP agreed at bid evaluation barg Contractual, from the TBE

(B) MAWP stated by the vendor barg From the vendor data book — the value under test

(i) Maximum discharge pressure, process barg From the process datasheet, if stated

(ii) Discharge line design pressure barg From the line list / piping specification

(C) Rating-floor override barg Enter the rating from your ASME B16.5 copy to bypass the embedded table

Hydrostatic stress ratio, Sec. 8.3.2.6 Allowable stress at test temperature ÷ at rated temperature; 1 if no correction

Reviewer remark Carried into the register and the export alongside the generated remark

3Calculated Pressures

Every intermediate value is shown so the result can be checked by hand. The row carrying the selected margin basis is highlighted.

Required minimum MAWP

—

Sec. 6.3.5

(B) MAWP stated by vendor

—

Margin against the requirement

(C) Sec. 6.3.5 rating floor

—

Hydrostatic test, Sec. 8.3.2.2

—

1.5 × MAWP

Symbol	Parameter	Basis	Value

4MAWP Checks & Verdict

A check with no data entered is reported as not applicable rather than as a pass. The clause column names the requirement each check enforces.

Check	Clause	Criterion	Required	Actual	Margin	Result

—

Awaiting data

Enter the head, relative density, suction pressure and the vendor's MAWP.

—

5Material Check — API 610 Annex H

Table H.1 is normative and lists the material class for each pump part. Enter what the vendor has offered; the tool flags anything that is not the class material. Table H.2 specifications are guidance only — Sec. 6.12.1.2 requires the vendor to state the actual specification and grade.

Part	Compliance	Table H.1 material	Typical specification (Table H.2)	Offered	Result

—

No materials entered

Leave a part blank to omit it from the check.

6Pump Register

One row per pump, all sharing the check settings above. Click a row to open it in the detail view. Columns 1 to 7 are the checks of section 4 and Mat is the material check — P passes, F fails, R needs review, and a dash means not applicable. The register is held in this browser only.

IAppendix I — ASME B16.5 Pressure-Temperature Ratings

The table behind the Sec. 6.3.5 rating floor. Linear interpolation between tabulated temperatures is permitted by ASME B16.5; interpolation between pressure classes is not.

Material group

Pressure class

Temperature °C

Working pressure

—

Choose a group, class and temperature.

Temperature	Class 150	Class 300	Class 600

IIAppendix II — API 610 Annex H Material Classes

Table H.1 material classes for pump parts, with the typical specifications of Table H.2. Reproduced as an aid; the standard and the purchase order govern.

Material class

Part	Full compliance	Table H.1 material	Typical specification (Table H.2)

Class code. —

Class	Casing	Impeller	Shaft	Case wear rings	B16.5 group

§Notes & Conventions

Maximum discharge pressure. API 610 11th Ed. Sec. 3.22 and Sec. 6.3.1 define it as the maximum suction pressure plus the maximum differential pressure the pump develops with the furnished impeller at rated speed and the specified normal relative density. Sec. 6.3.2 allows the purchaser to specify an increase for a) maximum specified relative density, b) an impeller of maximum diameter or number of stages, and c) operation to trip speed. The head and relative density you enter set that basis, and the boxes in section 2 record which escalations they represent.
Required MAWP. Sec. 6.3.5 requires the MAWP to be at least the maximum discharge pressure plus 10 % of the maximum differential pressure, and not less than a pressure-rating floor that depends on the pump type. Note 3 to that clause states the 10 % margin is intended to accommodate the head increase of Sec. 6.1.4, higher speed in variable-speed pumps, and the head test tolerance of Sec. 8.3.3.3 b).
The rating floor. Sec. 6.3.5 a) applies to axially split pumps, one- and two-stage between-bearings pumps, and single-casing vertically suspended pumps: the MAWP shall not be less than the rating of an ISO 7005-1 PN 20 steel flange, or an ISO 7005-2 PN 20 cast iron flange, of a material grade corresponding to the pressure casing. Note 1 to the clause makes ASME B16.5 Class 150 equivalent to ISO 7005-1 PN 20, and ASME B16.1 Class 125 equivalent to ISO 7005-2 PN 20. Sec. 6.3.5 b) applies to all other pumps: a gauge pressure rating of at least 4 MPa (40 bar; 600 psi) at 38 °C (100 °F).
Temperature of the rating floor. Sec. 6.3.5 a) states no temperature for the flange rating, unlike b) which states 38 °C. This tool evaluates the floor at the temperature basis of the vendor's MAWP by default, which is the conservative reading and the one that makes the floor comparable with the MAWP it is being tested against. The selector in section 0 offers the design temperature and 38 °C as alternatives.
Cast iron. Sec. 6.12.1.6 permits material classes I-1 and I-2 only where the maximum allowable gauge working pressure does not exceed 1 725 kPa (17,25 bar; 250 psi). Cast iron flanges are covered by ASME B16.1, not B16.5, and their Class 125 rating varies with nominal size, so the tool does not compute a floor for those classes — enter it in the override field.
Hydrostatic test. Sec. 8.3.2.2 requires the test to be conducted with liquid at a minimum of 1,5 times the MAWP. Sec. 8.3.2.6 requires that pressure to be multiplied by the ratio of the allowable working stress at the testing temperature to that at the rated operating temperature where the latter is lower; enter that ratio in section 2 if it applies. Sec. 8.3.2.11 requires the test to hold without leakage or seepage for 30 min. Sec. 6.13.2 requires the casing hydrostatic test pressure, the MAWP and the temperature basis for the MAWP to be stamped on the nameplate.
Materials. Sec. 6.12.1.1 makes the material class the purchaser's to specify, and Table G.1 is the informative selection guide. Table H.1 is normative and lists the material for each part, marking those with strength or pressure-integrity requirements as full-compliance parts under Sec. 6.12.1.4. Table H.2 gives corresponding international specifications for guidance only; Sec. 6.12.1.2 requires the vendor to state the actual specification and grade in the proposal.
Vertically suspended pumps. For type VS4 and VS5 in open-system sump service, Sec. 9.3.12.3 makes the casing, suction cover and discharge line the pressure-containing components; in closed-system pressurised or vacuum tank service the seal chamber, pump cover plate and tank cover become pressure-containing as well. Sec. 9.3.12.7 requires the discharge nozzle and cover plate to be designed to Sec. 6.3.3.
Constants. Differential pressure is H × SG × 0.0980665 bar per metre in SI, taking water at 1 000 kg/m³ and g = 9.80665 m/s², and H × SG × 0.4335 psi per foot in English units. All pressures are gauge.
ASME B16.5 data. The pressure-temperature ratings in Appendix I are transcribed for convenience and are marked as unverified until checked against a licensed copy of the standard. Any result that depends on them carries that warning. The override field in section 2 bypasses the table entirely.

Scope. This tool covers the pressure-containment requirements of Sec. 6.3.5, the hydrostatic test pressure of Sec. 8.3.2, and the material class of Annex H. It does not evaluate the nozzle-load design case of Sec. 6.3.3, the allowable stresses and casting factors of Sec. 6.3.4, the 3 mm corrosion allowance of Sec. 6.3.7, the inner-casing differential of Sec. 6.3.8, the radially split casing requirements of Sec. 6.3.9, bolting or gasket design, casing thickness, or any hydraulic or NPSH criterion. It is a check on the numbers a vendor has stated, not a substitute for the vendor's casing design calculation.