Vibrating piping and line movement

Who shall report vibrating or swaying piping?

Operating personnel

Who shall receive and assess the report of vibrating or swaying piping?

Engineering or inspection personnel

What other findings should be reported?

Movements due to liquid hammer, liquid slugging in vapor lines, or abnormal thermal expansion

How to inspect these lines?

Perform periodic MPT or DPT at restrained junctions, to check for fatigue cracks. Pay special attention to branch connections

What are examples of supplemental inspection?

✓ RT or thermography to check for fouling or internal plugging

✓ Thermography to check for hot spots in internally lined refractory lines

✔️ Inspection for environmental cracking

✓ AE, acoustic leak detection, thermography for remote leak detection and surveillance 

✓UT or RT for localized corrosion

Thickness measurement locations

What shall influence selection of CML?

Potential for localized corrosion and service specific corrosion

CML monitoring

Each piping system shall be monitored by taking thickness measurements at CML

Piping with higher potential of failure consequences and those with high corrosion rates, should have more CML and be inspected more often

What are typical circumstances where number of CML may be reduced?

✓ Olefin plant cold side piping

✓ Anhydrous ammonia piping

✓Clean noncorrosive hydrocarbon product

✓ High alloy piping for product purity