# Where does the Intergovernmental Panel on Climate Change say glass wool and rock wool emissions are reported, given that two of its passages differ?

Canonical: https://senseible.earth/answers/ipcc-rock-wool-glass-wool-which-reporting-line

The Intergovernmental Panel on Climate Change (IPCC) glass section includes glass wool in glass production and says emissive rock wool goes under subcategory 2A5. Its Table 2.7 says mineral wools go under 2A3 glass production or 2A4d other, depending on the process. The two passages do not match.

## What each passage says

- Section 2.4.1 (glass): "This source category also includes emissions from the production of glass wool, a category of mineral wool, where the production process is similar to glass making." Then: "Where the production of rock wool is emissive these emissions should be reported under IPCC Subcategory 2A5."
- Table 2.7 (uses of carbonates): mineral wools are marked emissive, reported under "2A3 Glass Production or 2A4d Other, depending on production process".

## Where they differ

For rock wool the glass section names 2A5 and the table names 2A3 or 2A4d. For glass wool the two agree on glass production, 2A3, as far as the glass section goes. I could not find a sentence in this chapter that settles the rock wool line, so I cannot say which is right.

## Two things the guide leaves out of the count

- "Emissions related to slag production should be reported in the relevant metallurgical source category."
- "The re-melting of slag to make mineral wool does not involve significant process-related emissions and does not need to be reported."

## What a unit can do

- The line number matters to a national inventory. A buyer or lender asking for a plant footprint wants the tonnes of each input and the fuel, so keep those records whichever line turns out to be right. This is my reading.
- Keep apart: limestone, dolomite or soda ash charged to the melter, coke or gas burnt in it, and fuel for the binder curing oven.
- If a form names a line, use theirs, and note that the guide's glass section and its Table 2.7 differ.

## What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so the fuel and power lines of a furnace or kiln are on file. The IPCC line is a choice you make with your buyer or adviser.

- [Rock wool carbon footprint per kg](https://senseible.earth/answers/rock-wool-insulation-carbon-footprint-per-kg)
- [Glass wool carbon footprint per kg](https://senseible.earth/answers/glass-wool-insulation-carbon-footprint-per-kg)
- [Which limestone uses release carbon dioxide](https://senseible.earth/answers/which-limestone-uses-release-carbon-dioxide)
- [IPCC glass factors and cullet ratios](https://senseible.earth/answers/ipcc-glass-default-factors-by-glass-type-and-cullet)

Sources: [IPCC, 2006 Guidelines, Volume 3, Chapter 2: Mineral Industry Emissions](https://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/3_Volume3/V3_2_Ch2_Mineral_Industry.pdf)

Last reviewed 2026-11-06. Quotes and figures are from the 2006 IPCC Guidelines, Volume 3, Chapter 2. The 2019 Refinement was not checked for this page; check it if a buyer names it. The glass section and Table 2.7 disagree on the rock wool line; check whether a later IPCC document corrects it.