Design Solution · MEP
Design Solution · Dream about it
Estimate embodied carbon of MEP equipment using CIBSE TM65 where EPDs are missing.
MEP plant has historically been left out of building life-cycle assessments because product EPDs were scarce. CIBSE TM65 provides a method to estimate the embodied carbon of mechanical, electrical and plumbing equipment from material quantities and proxy factors, accounting for large material masses, complex supply chains and high replacement rates (services replaced every 5-20 years). It brings MEP into whole-life carbon decisions.
CIBSE TM65 provides a systematic method to estimate the embodied carbon of MEP equipment when product EPDs are absent — filling a gap that has historically left services plant, with its large material mass, complex supply chains and high replacement frequency, effectively invisible in whole-life carbon assessments. The method is published, freely available, and increasingly referenced in UK practice as part of RIBA 2030 Challenge reporting and GLA compliance requirements, making it less a speculative innovation and more an emerging standard practice. This record is at claimed status with no project-specific verified evidence, though the methodology itself has a published basis and CIBSE validation. The value of applying TM65 is that it gives design teams a credible and auditable basis for including services in lifecycle carbon comparisons — relevant when evaluating, for instance, ground-source heat pump systems with high refrigerant and copper content against air-source alternatives, or assessing the carbon cost of replacing services every 15 years versus extending lifespan. The honest limitation of TM65 is that it uses material-quantity proxies and average carbon factors in the absence of real EPDs, so the estimates carry inherent uncertainty ranges; it is an improvement on omitting MEP from the assessment, but it should not be presented to clients as equivalent in accuracy to EPD-based calculations. The priority use is driving design decisions and identifying high-impact equipment categories, not producing a precise carbon certificate.
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