# At what temperature does each product fire at Virudhachalam, and why does that change the fuel per kilogram?

Canonical: https://senseible.earth/answers/virudhachalam-firing-temperature-by-product

The Energy and Resources Institute (TERI) profile gives firing temperatures of 1,130 to 1,140 degrees Celsius (°C) for red clay products, 1,180 for lamps, 1,190 for toys and 1,260 for heavy refractory bricks. Tunnel kiln firing zones run 1,130 to 1,260 °C by product, so a kiln log needs the product on each line.

## The firing temperatures

The profile says different ceramic products need different temperature profiles, and that energy use depends on the product and its firing temperature as well as the kiln type.

- Red clay products: 1,130 to 1,140 °C
- Lamps: 1,180 °C
- Toys: 1,190 °C
- Heavy products (refractory bricks): 1,260 °C

## Kiln by product

- Tunnel kilns, 5: three fire ceramics on rubber process oil or light diesel oil at about 7.5 tonnes a day; two fire high alumina refractory bricks on pet coke and imported coal dust at about 20 tonnes a day. Firing zone 1,130 to 1,260 °C.
- Shuttle kilns, 20: mainly toys, soaked about one hour, then forced cooling to about 200 to 250 °C.
- Rotary kilns, 10: pulverised coal. Downdraft kilns, about 100 built and about 20 firing: firewood, mainly bottom boring sets for steel plants.

## Heat per kilogram of ware

The profile's table gives tunnel 1,740 kilocalories (kcal) a kilogram or 7.3 megajoules (MJ), shuttle 3,779 or 15.8, rotary 1,413 or 5.9 and downdraft 4,200 or 17.6. The text above it says 5.9 megajoules per tonne to 17.6 per tonne. The table's per kilogram column is the one that matches the kilocalorie column: 1,413 x 4.1868 = 5,916 kilojoules, or 5.9 MJ.

## Ceramic against refractory tunnel kiln

The profile's typical-unit table gives thermal energy of 138 tonnes of oil equivalent (toe) a year for a ceramic tunnel kiln and 633 for a refractory one. At about 7.5 and 20 tonnes a day, that is 18.4 and 31.65 toe a year for each tonne a day of capacity. The refractory kiln uses about 1.7 times as much. This assumes both run the same days and that the typical unit matches the stated capacity, which the profile does not say. That reading is mine.

## What to log

- The product and set temperature on every firing line.
- Fuel by kiln, so one kiln's refractory work is not blended with another's ceramics.
- Hours at peak, since the refractory bricks sit at the top of the range.

## Capacity-adjusted heat from the profile's table

- Ceramic tunnel kiln: 138 toe / 7.5 tonnes a day = 18.4 toe a year for each tonne a day
- Refractory tunnel kiln: 633 toe / 20 tonnes a day = 31.65
- Ratio: 31.65 / 18.4 = 1.72

Both figures come from the profile's typical-unit table and stated capacities. Operating days are not printed.

## 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. In the self-serve product it does not read kiln temperature settings; custom sensors are available on request, so the product and temperature log is yours to keep.

- [Virudhachalam kiln fuel and carbon](https://senseible.earth/answers/virudhachalam-ceramic-refractory-kiln-fuel-carbon)
- [Kiln temperature log a verifier wants](https://senseible.earth/answers/kiln-temperature-log-what-verifier-wants)
- [Tunnel kiln heat per kg in two profiles](https://senseible.earth/answers/tunnel-kiln-heat-per-kg-khurja-and-virudhachalam)
- [Tunnel kiln against shuttle kiln emissions](https://senseible.earth/answers/tunnel-kiln-vs-shuttle-kiln-emissions)

Sources: [TERI, Cluster profile: Vriddhachalam ceramics and refractory industries (SAMEEEKSHA)](https://sameeeksha.org/pdf/clusterprofile/Virudhachalam-Ceramics-Refractories-TamilNadu.pdf)

Last reviewed 2026-11-06. Figures are from TERI's 2015 cluster profile, which describes the cluster at that time; fuels, kiln counts and prices have moved since. Treat them as typical, and check your own records before quoting.