---
title: "ASME PTC 4"
description: "ASME PTC 4 (American Society of Mechanical Engineers Performance Test Code 4) specifies the standard methodology for fired-steam-generator performance tests. PTC 4 measurements quantify boiler efficiency, individual heat losses (dry gas, moisture, unburned carbon, radiation, etc.) and the contribution of convective-pass fouling to overall performance."
canonical_url: "https://sylio.co/glossary/asme-ptc-4"
last_updated: "2026-06-28T02:29:38.052Z"
---

**ASME PTC 4** (American Society of Mechanical Engineers Performance Test Code 4) specifies the standard methodology for fired-steam-generator performance tests. PTC 4 measurements quantify boiler efficiency, individual heat losses (dry gas, moisture, unburned carbon, radiation, etc.) and the contribution of [convective-pass fouling](/glossary/convective-pass-backpass) to overall performance.

## Why it matters for sonic-horn business cases

A PTC 4 test before and after a [sonic-horn](/glossary/sonic-horn) installation quantifies the [heat-rate](/glossary/heat-rate) improvement attributable to the cleaning system. Independent PTC 4 measurements provide third-party-credible evidence of acoustic-cleaning ROI, which is particularly valuable for utility-scale procurement decisions where multiple stakeholders must approve capital spend.

## Related terms

- [Boiler](/glossary/boiler)
- [Heat rate](/glossary/heat-rate)
- [Economiser](/glossary/economiser)
- [Air heater](/glossary/air-heater)