The tonnage of a steam boiler is actually the rated evaporation capacity per hour, with the unit being tons per hour (t/h), indicating how many tons of water can be converted into saturated steam in one hour.

1.How to Classify Tonnage (The Most Commonly Used Standard)
In the industry, it is generally divided into four grades based on evaporation volume:
Small boiler
0.1 to 1 ton per hour
Usage: Small canteens, laundries, small-scale food processing, laboratories, small-scale disinfection
Medium-sized boiler
2 to 10 tons per hour
Usage: Garment factories, food factories, pharmaceutical factories, small chemical plants, and heating in residential areas
Large boiler
10 to 35 tons per hour
Application: Medium-sized factories, centralized heating, papermaking, building materials
Super-large boiler
More than 35 tons per hour
Application: Thermal power plants, large-scale chemical plants, large industrial parks

2.What you care about most: How to choose tonnage?
Simple formula (estimation) :
Required tonnage ≈ Total steam consumption of steam-using equipment ÷ 0.8 (Safety factor)
Common scenario references
One ton of steam ≈ provides 600,000 calories of heat
A 1-ton boiler can provide heating for 6,000 to 8,000 square meters of building area
Food steaming: Generally 0.5 to 2 tons
Garment factory: Generally 1 to 4 tons

3.Tonnage ≠ Weight! Don’t get confused.
Many people misunderstand
It’s not about how many tons the boiler itself weighs
It is how many tons of steam are produced per hour
If you tell me what it is for, the size of the site and the pressure requirements, I can directly help you calculate how many tons of boiler should be used.