Learning from Failure: Real Project Lessons When ASME B16.20 Was Not Properly Followed

The project was a high-pressure steam system retrofit for a mid-sized chemical processing plant. The goal was to increase capacity and efficiency by upgrading several critical piping runs. The design team, under pressure to meet an aggressive schedule, focused on the primary pipe and valve specifications.

Gaskets were treated as a commodity item, a simple line on the material take-off. The prevailing attitude was that a gasket is a gasket, as long as it fit the flange dimensions. The procurement team sourced what was readily available and cost-effective, with the assumption that any compliant spiral-wound gasket would suffice.

The first signs of trouble appeared during the hydrotest phase. Several flanges on the new 600-pound class steam lines showed persistent, weeping leaks. The initial response was to simply increase the bolt torque. This stopped some leaks but created new ones at adjacent joints, a classic case of solving one problem by creating another.

During plant startup, when live steam was introduced, the situation worsened. A major leak developed at a critical manifold, forcing an emergency shutdown. The resulting downtime and lost production immediately erased any cost savings from the initial gasket selection.

Where the Project Team Misjudged the Requirements

The core misunderstanding was viewing ASME B16.20 as merely a dimensional standard. The team checked that the inner diameter and outer diameter of the gaskets matched the flanges. They believed this was the extent of compliance. This was a fundamental and costly error.

The standard categorizes gaskets by type, style, class, and facing. The project used a generic “spiral-wound, 304SS/FG” designation. This ignored the critical “class” designation, which defines the pressure-temperature rating and construction details like the number of spiral plies and the presence of inner and outer rings.

For the 600-class flanges on a steam service, the standard specifies requirements for centering rings and controlled compression. The installed gaskets lacked proper inner rings. This allowed the spiral winding to potentially intrude into the flow path under high pressure and also made the gasket less stable during bolt-up.

How Inspectors Usually Identify These Problems

A seasoned inspector doesn’t just check material certificates. They perform a physical audit of the gaskets on-site before installation. They look for the permanent, metal tag or embossed marking required by B16.20. This marking tells the full story: manufacturer, size, class, material, and standard.

On this project, many gaskets had only a paper tag that was lost or damaged. The lack of permanent marking was the first red flag. Inspectors also compare the gasket’s physical construction to the project’s piping specifications and the flange facing. The absence of a visible inner ring on a gasket destined for a high-pressure steam service would trigger an immediate hold.

During bolt-up observation, inspectors watch for gasket behavior. A gasket without proper reinforcement may buckle or twist as bolts are tightened, rather than compressing evenly. This uneven compression is a direct precursor to the channel leaks experienced during hydrotest.

What Should Have Been Controlled Earlier

Control needed to start at the specification stage. The piping design specification must explicitly call out the required B16.20 gasket class and style for each service, not just a generic description. This transforms the gasket from a commodity into a specified engineered component.

Procurement must then enforce this specification with vendors. Requiring certified material test reports that trace back to the standard’s marking requirements is essential. Substitutions should require formal review by engineering, not just a procurement clerk checking for dimensional fit.

The greatest leverage point is pre-installation verification. A simple “kitting” process, where gaskets are matched to their specific flange joints in a controlled environment before being sent to the field, would have caught the mismatch. This is where the inspector’s eye for the permanent marking is invaluable.

The Real-World Function of the Standard

ASME B16.20 provides a common language for integrity. It ensures that when an engineer specifies a “B16.20, Style R, Class 600, 304SS/Graphite” gasket, everyone in the chain—manufacturer, distributor, installer, inspector—understands the exact physical and performance characteristics required.

This standardization prevents the “almost right” scenario that plagued this project. The installed gaskets were almost the right size and almost the right type. In high-pressure steam, “almost” results in leaks, shutdowns, and safety hazards. The standard defines the boundary of what is acceptable.

Furthermore, it ensures system compatibility. The gasket dimensions and performance are designed to work in concert with the flange standards (ASME B16.5) and the bolt-up practices (ASME PCC-1). Ignoring one element breaks the integrated sealing system the codes collectively create.

The Cost of Non-Compliance

The direct costs were significant: lost production from the shutdown, labor for the rework, and the expense of the correct, specified gaskets. But the indirect costs were more profound. The project team’s credibility with the client was damaged. The perceived “simple” gasket issue undermined confidence in the entire system’s design and installation.

The rework itself was disruptive. Re-gasketing under time pressure in a live plant environment is far more difficult and hazardous than doing it correctly the first time during construction. It required new isolation plans, hot work permits, and additional safety oversight.

Most importantly, the initial failure created an unseen risk. The gaskets that didn’t leak immediately under test might have been compromised or over-stressed by the excessive bolt torque used to stop the initial leaks. This creates a latent failure point that could manifest months later, turning a construction flaw into an operational reliability issue.

The Lesson Learned

The lesson is not to memorize B16.20 clauses. It is to understand its role as a quality assurance framework. It moves gasket selection from an afterthought to a deliberate engineering decision integrated with flange specification and joint assembly procedure.

On subsequent projects, we implemented a gasket management plan. It starts with explicit specification, includes certified procurement, mandates pre-installation marking verification by quality control, and requires documented bolt-up procedures. This plan treats the gasket with the same importance as the valve it seals.

The standard is a tool for risk mitigation. By following it, you are not just buying a piece of metal and filler. You are buying a predictable performance envelope, traceability, and system compatibility. In the end, that predictability is far cheaper than the cost of a leak.