ISO 6993-4:2006

Overview

ISO 6993-4:2006 is the code of practice for the design, handling and installation of buried, high‑impact poly(vinyl chloride) (PVC‑HI) piping systems used to supply gaseous fuels. It applies to mains and service lines with an operating temperature range of 0 °C to +30 °C, a maximum operating pressure of 1 bar (100 kPa), and pipe/fitting outside diameters up to 400 mm. The standard complements product specifications (ISO 6993‑1, ‑2, ‑3) and covers trenching, backfilling, storage, transportation, jointing, testing and commissioning.

Key topics and requirements

• Scope & applicability: Buried PVC‑HI systems for gases that do not chemically damage pipe material; mains and service lines up to OD 400 mm.
• Design requirements: Written laying procedures authorized by the pipeline operator; selection of materials, SDR series and assembly techniques to be defined by the operator.
• Materials & components: Pipes per ISO 6993‑1; common SDRs (e.g., 41, 33); rubber seals per EN 682; polyethylene service lines per ISO 4437 and ISO 8085.
• Assembly techniques:
  • End‑thrust (mechanical) joints required for systems with MOP > 200 mbar and ≤ 1 bar (per ISO 6993‑3).
  • Push‑in/socket joints permitted for MOP ≤ 200 mbar (per ISO 6993‑2).
  • Solvent‑cement socket joints and mechanical metal‑to‑PVC‑HI transition joints described.
  • Use of tapping saddles, bag stopper saddles and flanged joints (ISO 7005) for ancillaries.
• Installation practice: Installer competence and formal training; manufacturer’s written jointing instructions; cutting, bevelling, lubrication and cleanliness for reliable joints.
• Storage, handling & transport: Procedures to prevent damage and contamination before installation.
• Quality control & testing: Provisions for pressure testing, commissioning and documentation (see EN 12327 for test procedures).

Applications and users

• Practical for gas distribution network designers, pipeline operators, civil contractors, installation crews, and manufacturers of PVC‑HI pipes and fittings.
• Typical applications: buried distribution mains, service connections to consumers, temporary isolation using bag stoppers, and metal‑to‑PVC transitions for valves and fittings.
• Useful for drafting installation procedures, training installer competency programs, and ensuring compliant on‑site practices for safety and long‑term performance.

Related standards

• ISO 6993‑1, ISO 6993‑2, ISO 6993‑3 (PVC‑HI system parts)
• ISO 4437, ISO 8085 (PE service lines/fittings)
• EN 682 (elastomeric seals), EN 12327 (pressure testing)
• ISO 7005 (flanges), ISO 7387‑1 (solvent adhesives)
• ISO 4065, ISO 161‑1 (dimension series and SDR references)

Keywords: ISO 6993-4:2006, PVC‑HI piping, buried gas pipelines, code of practice, design, handling, installation, pressure testing, tapping saddle, bag stopper.