For the MRc4.1 Materials calculations for a fume hood intensive laboratory building, under LEED-NC v2.1, we would need to use 45% x Total Project Cost, TPC, as the default value for the denominator in calculations. The LEED For Labs application guide, brings that multiplier down to 32% to account for expensive lab mechanical systems and equipment. However, we understand that 32% was based on less than a dozen actual lab building project costs from around the US, which vary greatly. The LEED-NC v2.1 default value of 45% as this was developed for a typical office building and not a laboratory building. The USGBC\'s default value of 45% is assumed to be the cost of all Div 2-10 materials (without installation costs) in the project. Since the majority of a new lab building\'s costs are MEP and lab equipment, we feel using this value of 45% x the total cost of the project is incorrect. We feel a correct amount for the denominator of the calculation should be the total project costs minus all MEP costs multiplied by 45%. Please let us know for this credit and other MR credits 3-6, if we can exclude MEP costs from the total project cost, TPC, to get an adjusted TPC and then multiplying this adjusted TPC by 45% to use as the denominator.
The MRc4 calculation strategy proposed is not acceptable. The Reference Guide states that total materials cost may be derived from a default calculation OR a tally of actual material costs. The default value is meant to establish an easy and convenient way for project teams to generate an approximate value of the total material cost By providing total construction (hard) costs. If using the default value is not appropriate for your project type, you must tally actual material costs for CSI MasterFormat Divisions 2-10. The v2.0 calculator, available on the LEED-NC project resources web page, is a helpful tool for this calculation.