What international standards govern sampling system selection, design, installation and operation? There are four major standards that govern Sampling liquid hydrocarbons in pipelines. They are ISO 3171, IP 6.2, API 8.2 and ASTM D4177. Equipment that complies with ISO 3171 will comply with the other standards, so we have used it as the guiding standard. In the teach me section of this web site we discuss and provide guidance on the requirements of the standards. CONTINUE READING DESIGN ISSUES: WHAT ARE THE MOST IMPORTANT STEPS TO CONSIDER WHEN DESIGNING OR SPECIFYING A SAMPLING SYSTEM?