API 676 Requirements for Screw Pumps - Standard Compliance Guide

API 676 Scope and Coverage

Standard Overview

API Standard 676 - Positive Displacement Pumps—Rotary

Pump Types Covered

Design Requirements

General Design Principles

Pressure Containment

Corrosion Allowance

Standard Requirement: 3 mm (0.12") minimum on all pressure-containing parts

Exceptions:
- Superior corrosion-resistant materials may use less
- Must be documented with material data
- Process engineer approval required

Nozzle Requirements

Pressure Protection

Mandatory Relief Valve

API 676 Requirement: Every positive displacement pump MUST have pressure-limiting protection.

Relief Valve Location Options

Pressure Protection Verification

Checklist:
□ Relief valve included in scope
□ Set pressure documented (≤ 110% Poperating)
□ Capacity verified (full pump flow)
□ Materials compatible with fluid
□ Discharge piped safely

Material Requirements

Standard Materials

Material Certification

Corrosive/Special Service

Mechanical Seal Requirements

API 682 Reference

API 676 references API 682 for shaft sealing systems:

Seal Arrangement Options

Seal Flush Plans for Screw Pumps

Bearing Requirements

Design Life

Bearing Types

Lubrication

Testing Requirements

Factory Tests

Performance Tolerances

Witness Points

Documentation Requirements

With Quotation

With Shipment

Data Retention

Quality Assurance

Inspection and Test Plan (ITP)

Quality System Requirements

Nameplate Requirements

Required Information

NAMEPLATE DATA:
- Manufacturer name
- Model/Type
- Serial number
- Rated capacity (flow)
- Rated pressure (differential)
- Rated speed
- Maximum allowable working pressure
- Design temperature
- Year of manufacture

API 676 Compliance Checklist

=== API 676 COMPLIANCE VERIFICATION ===

Design:
□ Pressure containment per ASME
□ Corrosion allowance ≥ 3 mm (or justified)
□ Nozzles per ASME B16.5
□ Drain and vent provided

Pressure Protection:
□ Relief valve included
□ Set pressure ≤ 110% operating
□ Capacity = full pump flow
□ Discharge safely piped

Materials:
□ Material specifications listed
□ MTRs required for pressure parts
□ NACE compliance (if H₂S service)

Sealing:
□ API 682 seal arrangement specified
□ Flush plan selected
□ Seal materials compatible

Bearings:
□ L10 life ≥ 25,000 hours
□ Lubrication system adequate

Testing:
□ Hydrostatic test 1.5× MAWP
□ Performance test at rated
□ Mechanical run test 4 hours

Documentation:
□ Certified datasheet
□ Performance curves
□ Material certificates
□ Manuals (IOM)
□ Spare parts list