SIST EN 286-1:1998/A2:2006

Overview

SIST EN 286-1:1998/A2:2006 is a critical European standard developed by CEN for simple unfired pressure vessels designed to contain air or nitrogen. This document specifically addresses Part 1, which covers pressure vessels for general purposes. The amendment introduced in 2005 (A2) adds a new normative Annex H that details the requirements for peaking-local irregularities or out-of-roundness caused by weld misalignment or profile deviations.

This standard ensures the structural integrity and safety of pressure vessels under various loading conditions by providing clear criteria for allowable imperfections and specifying precise measurement methods. SIST EN 286-1:1998/A2:2006 must be implemented by CEN member countries, reflecting harmonized safety and quality expectations across Europe.

Key Topics

• Scope and Purpose
  Focus on simple unfired vessels for air or nitrogen containment, intended for general industrial and commercial use.

• Peaking Requirements
  Annex H introduces detailed requirements on peaking, which is defined as out-of-roundness caused by weld joint misalignment or local profile irregularities.

• Measurement Methods
  Peaking must be measured using a 20° profile gauge, bridge gauges, or needle gauges. Measurements are taken at approximately 250 mm intervals along the longitudinal welds to locate the maximum peaking.

• Limits for Irregularities

  • Local profile irregularities (e.g., dents or flats) should be smooth with a maximum depth of 2% to 2.5% of the gauge length.
  • Peaking at longitudinal welds has maximum allowable limits depending on vessel wall thickness and type of loading (dynamic/cyclic or static).

• Dynamic and Cyclic Loads
  Table H.1 specifies peaking limits for vessels under cyclic or dynamic loads, ranging from 1.5 mm up to 10 mm depending on wall thickness.

• Static Loads
  Table H.2 outlines peaking limits for pressure vessels under static (non-cyclic) loads with values based on the wall thickness to diameter ratio.

• Safety Assurance
  Any peaking values exceeding specified limits require additional proof through calculation or strain gauge measurements, with special analyses mandated for out-of-limit cases.

Applications

SIST EN 286-1:1998/A2:2006 is essential for manufacturers, designers, and inspectors involved in the production and certification of pressure vessels used in:

• Industrial compressed air systems
• Nitrogen storage and supply equipment
• General purpose pressure containers in manufacturing and process industries
• Safety inspections and compliance testing of new or existing unfired pressure vessels
• Ensuring structural integrity against stress concentrations caused by weld imperfections

By adhering to this standard, stakeholders can minimize failure risks due to local deformation or peaking, improving overall vessel reliability and operational safety.

Related Standards

• EN 13445 – Unfired Pressure Vessels series, particularly Part 4: Design for pressure vessels, and Parts 3 and 5 for cyclic loading considerations, referenced for additional peaking requirements and strain analysis.
• CEN/CENELEC Internal Regulations – Ensure consistent application and national implementation of European standards.
• ISO Standards related to pressure vessel design and testing complement the guidelines in EN 286-1.

Keywords: SIST EN 286-1:1998/A2:2006, unfired pressure vessels, air pressure vessels, nitrogen containment, peaking requirements, pressure vessel design, welding irregularities, pressure vessel safety, European standard, pressure vessel inspection, CEN, pressure vessel measurement