GB/T 32224-2020Heat meters (English PDF)

Foreword

GB/T 32224-2020 was issued on 19 November 2020 by the State Administration for Market Regulation and the Standardization Administration of the People's Republic of China, and has been in force since 1 October 2021. It replaces GB/T 32224-2015, the only previous edition.

This standard was proposed by the Ministry of Housing and Urban-Rural Development of the People's Republic of China, and was prepared by SAC/TC 455 on Municipal Heating-supply of the Standardization Administration of China.

Among the changes made with respect to the 2015 edition: the overall requirements for data interface and communication are modified (see Annex C); the measurement point requirements for the overall test of the heat meter are modified and test points for cooling meters added (see Table D.1); requirements for confirmation of the display value during the overall test are added (see D.2.3); the test temperature points of the calculator are modified and requirements for testing the calculator of meters for heating and cooling added (see Table E.1 and E.1); requirements for simulated flow signals during calculator testing are added (see E.2.3); the temperature test range of the temperature sensor is modified (see F.2.1); special requirements for testing flow sensors larger than DN250 are added (see G.2.1); requirements on water temperature change during the flow sensor test are added (see G.2.2); and the test requirements for electromagnetic compatibility are modified (see Annex H).

1 Scope

China's national standard for heat meters - the instruments that measure how much thermal energy a building actually takes from a district heating network. For most of the history of Chinese district heating the bill did not depend on consumption at all: an apartment paid by floor area, so closing a radiator saved the occupant nothing and the network had no way to reward anyone for using less. Metering is what turns heat into something that can be sold by the unit, and it is harder than metering electricity, because the quantity is not measured directly. A heat meter infers energy from three separate measurements - the volume flowing, the temperature at the inlet and the temperature at the return - and a small error in the temperature pair becomes a large error in the bill, since the difference between the two may be only a few degrees. That is why this standard devotes nine normative annexes to error testing, temperature sensor construction, electromagnetic compatibility and flow disturbance. It specifies the terms and definitions, symbols, technical characteristics, requirements, test methods, inspection rules, and the marking, packaging, transport and storage of heat meters, and applies to the manufacture and inspection of meters using water as the medium; for other liquids it can be applied once the specific enthalpy and density of that liquid are known.

This standard specifies the terms and definitions, symbols, technical characteristics, requirements, test methods, inspection rules as well marking, packaging, transport and storage of heat meters.

This standard is applicable to the manufacture and inspection of heat meters using water as the medium. When the medium is other kinds of liquid, this standard can be implemented after obtaining the specific enthalpy and density parameters of the liquid.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 191 Packaging - Pictorial marking for handling of goods.

GB/T 1800.2 Geometrical product specifications (GPS) - ISO code system for tolerances on linear sizes - Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts.

GB/T 2423.1, GB/T 2423.2, GB/T 2423.3 and GB/T 2423.4 Environmental testing for electric and electronic products - cold, dry heat, damp heat steady state and damp heat cyclic.

GB/T 4208-2017 Degrees of protection provide by enclosure (IP code); GB 4706.1-2005 Household and similar electrical appliances - Safety - Part 1: General requirements.

GB/T 7307 Pipe threads with 55 degree thread angle where pressure-tight joints are not made on the threads; GB/T 9124.1 and GB/T 9124.2 Steel pipe flanges; GB/T 17241.6 Integral cast iron flanges.

GB/T 9254 Information technology equipment - Radio disturbance characteristics - Limits and methods of measurement.

GB/T 17626.2, GB/T 17626.3, GB/T 17626.4, GB/T 17626.5, GB/T 17626.6-2017, GB/T 17626.8 and GB/T 17626.11 Electromagnetic compatibility - Testing and measurement techniques.

GB/T 26831.1, GB/T 26831.2, GB/T 26831.3 and GB/T 26831.6 Society energy metering for reading system specification.

GB/T 30121-2013 Industrial platinum resistance thermometers and platinum temperature sensors; CJJ 34 Design code for city heating network.

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.