# ASTM D6132

Source: https://coatmentor.com/standards/astm-d6132/ · Updated 2026-10-14

Dry film thickness by ultrasonic gauge, also on concrete, wood and plastic.

**Publisher**: ASTM International

**Area**: Application and film thickness

ASTM D6132 covers ultrasonic gauges that measure the thickness of organic coatings without damaging them. Their great use is on substrates where magnetic and eddy-current gauges cannot work: concrete, wood, wallboard, plastic and composites. They also work on metal.

## How the gauge works

The probe sends a sound pulse through a couplant into the coating. The pulse reflects at the interface with the substrate, and the gauge turns the travel time into thickness. In a system of several coats it finds the interface with the greatest acoustic difference; some gauges show each layer.

## Points to remember

- A couplant is needed for each reading: water on smooth coatings, a gel on rough ones.
- Verify the gauge on reference standards of known thickness.
- Soft coatings that deform under the probe are outside the method. Air voids and heavily filled or flake-filled coatings can give low readings.
- D6132 tells how to take a reading, not how many. SSPC-PA 9 gives the number of readings on non-metal substrates.

**10** practice items in the members area mention ASTM D6132 (CIP 1: 2 · CIP 2: 7 · FROSIO written: 1).

## Related

- **Concepts:** [Dry film thickness measurement](https://coatmentor.com/learn/dft-measurement/)
- **Standards:** [SSPC-PA 9](https://coatmentor.com/standards/sspc-pa-9/) · [ASTM D7091](https://coatmentor.com/standards/astm-d7091/) · [ASTM D4138](https://coatmentor.com/standards/astm-d4138/)

## About this page

This page describes the subject of ASTM D6132 in our own words; it does not reproduce the standard. For the full text, buy the current edition from ASTM International. Checked on 2026-10-14; errors go in the [corrections log](https://coatmentor.com/method/). CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.