# ASTM D6878

> ASTM D6878 is the North American material specification for thermoplastic polyolefin (TPO) sheet used as single-ply roofing membrane.

- URL: https://roof.wiki/astm-d6878/
- Topic: Standards, Codes & Testing
- Also known as: D6878; TPO standard; ASTM D 6878
- Regions: North America
- First published: 2026-11-02 · Last reviewed: 2026-11-02
- Cite as: "ASTM D6878." roof.wiki. https://roof.wiki/astm-d6878/

## Key facts

- **Publisher:** ASTM International
- **Active version:** D6878/D6878M-26
- **Material:** Thermoplastic polyolefin (TPO) sheet
- **Seaming:** Heat-welded
- **Scope limit:** Material only; not in-place roof design

ASTM D6878/D6878M, *Standard Specification for Thermoplastic Polyolefin Based Sheet Roofing*, sets minimum material requirements for TPO roofing membranes. TPO is a heat-weldable single-ply membrane widely used on low-slope commercial roofs in North America and increasingly elsewhere. ASTM lists D6878/D6878M-26 as the active version.

## What it covers

The specification applies to flexible sheet made with thermoplastic polyolefin as the principal polymer, intended for use as single-ply roofing exposed to the weather. Requirements include properties such as:

- overall sheet thickness and thickness of the coating over the reinforcing scrim
- breaking strength and elongation
- tearing strength
- low-temperature brittleness
- dimensional stability
- heat ageing and resistance to ultraviolet light and weathering

Like other ASTM membrane specifications, D6878 deals with the sheet as manufactured. In-place roof performance, such as fire rating, wind uplift and seam strength in the field, is covered by system tests and code requirements, for example [UL 1897](https://roof.wiki/ul-1897/), [FM 4470](https://roof.wiki/fm-4470/) and [ASTM E108](https://roof.wiki/astm-e108-ul-790/).

## About TPO

TPO compounds blend a thermoplastic such as polypropylene or polyethylene with an elastomer such as EPDM, plus fillers and stabilizers. TPO resists ultraviolet degradation and is usually white or light-coloured, which makes it common where reflective "cool roof" performance is wanted. Seams are joined by hot-air welding.

The specification has been revised several times as the industry gained field experience with the material.

## Market context

Thermoplastic membranes (TPO and PVC, plus KEE) together account for a large share of the US commercial roofing market. Competing single-ply membranes are PVC under [ASTM D4434](https://roof.wiki/astm-d4434/) and EPDM under [ASTM D4637](https://roof.wiki/astm-d4637/).

## Outside North America

In Europe, flexible thermoplastic membranes are specified under a harmonised European standard for plastic and rubber roof waterproofing sheets, which covers several polymer types rather than TPO alone; polyolefin membranes there are often called FPO (flexible polyolefin).

## Sources

1. Standard Specification for Thermoplastic Polyolefin Based Sheet Roofing — ASTM International. https://store.astm.org/standards/d6878
2. Membrane roofing — Wikipedia. https://en.wikipedia.org/wiki/Membrane_roofing
3. Thermoplastic polyolefin — Wikipedia. https://en.wikipedia.org/wiki/Thermoplastic_polyolefin