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ITU-T L.1322 (12/2025)

Multi-level metrics for thermal environment and thermal performance of data centres

Recommendation ITU-T L.1322 specifies a quantitative evaluation framework for the thermal environment of data centres characterized by high heat-flux density, stringent environmental requirements, and refrigeration systems with year-round operation. The framework defines multi-level indicators: room-, row-, cabinet-, device-, and chip-level, covering airflow organization and cooling effectiveness. The framework supports identifying hot spots, optimizing airflow patterns, reporting safety levels, and quantifying energy use and savings potential, and it enables comparison across data centres of different sizes, layouts, and airflow schemes.

Citation:	https://handle.itu.int/11.1002/1000/16637
Series title:	L series: Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation and protection of cables and other elements of outside plant L.1300-L.1399: Energy efficiency, smart energy and green data centres
Approval date:	2025-12-14
Provisional name:	L.thermal_DC
Approval process:	AAP
Status:	In force
Maintenance responsibility:	ITU-T Study Group 5
Further details:	Patent statement(s) Development history [52 related work items in progress]

Ed.	ITU-T Recommendation	Status	Summary	Table of Contents	Download
1	L.1322 (12/2025)	In force	here	here	here


ITU-T Supplement	Title	Status	Summary	Table of contents	Download
L Suppl. 4 (04/2016)	Guidelines for developing a sustainable e-waste management system	In force	here	here	here
L Suppl. 5 (12/2014)	Life-cycle management of ICT goods	In force	here	here	here
L Suppl. 6 (12/2014)	ITU-T L.1300 - Supplement on a validation test of a data centre cooling method using renewable energy in a cold region	In force	here	here	here
L Suppl. 7 (12/2014)	ITU-T L.1300 - Supplement on rationale for minimum data set for evaluating energy efficiency and for controlling data centre equipment in view of power saving	In force	here	here	here
L Suppl. 8 (12/2014)	ITU-T L.1300 - Supplement on potential for primary energy savings in TLC/ICT centres through free cooling	In force	here	here	here
L Suppl. 9 (12/2014)	ITU-T L.1300 - Supplement on case study of reduction of air-conditioning energy by optical fibre based thermometry	In force	here	here	here
L Suppl. 10 (12/2014)	ITU-T L.1300 - Supplement on verification experiments related to increase of efficiency of air-conditioning and control technologies at a data centre	In force	here	here	here
L Suppl. 11 (12/2014)	ITU-T L.1300 - Supplement on verification test and feasibility study of energy and space efficient cooling systems for data centres with high density ICT devices	In force	here	here	here
L Suppl. 12 (12/2014)	ITU-T L.1300 - Supplement on experimental studies on plates and ducts installed at equipment inlets and outlets	In force	here	here	here
L Suppl. 20 (10/2015)	Green public ICT procurement	In force	here	here	here
L Suppl. 21 (04/2016)	Implementation guidance for small- and medium-sized enterprises on information and communication technology supply chain due diligence concerning conflict minerals	In force	here	here	here
L Suppl. 27 (10/2016)	Supplement on success stories on e-waste management	In force	here	here	here
L Suppl. 28 (10/2016)	Circular economy in information and communication technology; definition of approaches, concepts and metrics	In force	here	here	here
L Suppl. 32 (10/2016)	Supplement for eco-specifications and rating criteria for mobile phones eco-rating programmes	In force	here	here	here
L Suppl. 33 (10/2016)	Assessment of energy consumption of information and communication technology services	In force	here	here	here
L Suppl. 41 (05/2021)	Requirements on energy efficiency measurement models and the role of artificial intelligence and big data	In force	here	here	here
L Suppl. 42 (05/2021)	Guidelines on the environmental efficiency of machine learning processes in supply chain management	In force	here	here	here
L Suppl. 43 (05/2021)	Smart energy saving of 5G base stations: Traffic forecasting and strategy optimization of 5G wireless network energy consumption based on artificial intelligence and other emerging technologies	In force	here	here	here
L Suppl. 46 (12/2021)	Definitions and recent trends in circular cities	In force	here	here	here
L Suppl. 47 (07/2022)	Examples of resource saving within the information and communication technology sector	In force	here	here	here
L Suppl. 49 (07/2022)	Overview on adaptation to climate change for information and communication technology networks	In force	here	here	here
L Suppl. 52 (10/2022)	Computer processing, data management and energy perspective	In force	here	here	here
L Suppl. 53 (10/2022)	Guidelines on the implementation of environmental efficiency criteria for artificial intelligence and other emerging technologies	In force	here	here	here
L Suppl. 54 (10/2022)	Guidance for assessing the greenhouse gas emissions consequences of the financial effects generated by information and communication technology	In force	here	here	here
L Suppl. 55 (10/2022)	Environmental efficiency and impacts on United Nations Sustainable Development Goals of data centres and cloud computing	In force	here	here	here
L Suppl. 56 (10/2022)	Guidelines for connecting cities and communities with the Sustainable Development Goals	In force	here	here	here
L Suppl. 63 (06/2026)	ITU-T L.1060 – Supplement on specific principles for the green supply chain management of information and communication technology manufacturing industry	In force	here	here	here
L Suppl. 65 (07/2026)	National experiences with respect to ITU-T L.1xx-series optical fibre cables, installation methods and test methods	In force	here	-	here

Title	Approved on	Download
Study on methods and metrics to evaluate energy efficiency for future 5G systems	2017	here
Partnering for solutions: ICTs in Smart Water Management	2014	here
Resilient pathways: the adaptation of the ICT sector to climate change	2014	here
Network infrastructure best practices	2013	here
Greening ICT Supply Chains – Survey on Conflict Minerals Due Diligence Initiatives	2012	here
Review of Mobile Handset Eco-Rating Schemes	2012	here
Boosting Energy Efficiency through Smart Grids	2012	here

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ITU-T L.1322 (12/2025)