Interior paint must always be included in Materials and Resources credits. This is because interior paint is considered as a permanently installed product, which is defined by the LEED v4 Reference Guide for Building Design and Construction as 'a product that is installed in a project permanently or semi-permanently, such that removal would require demolition or substantial renovation.'1 Permanently installed products must be included in the calculations for the following Materials and Resources credits: Building Life-Cycle Impact Reduction, Building Product Disclosure and Optimization - Environmental Product Declarations, Building Product Disclosure and Optimization - Sourcing of Raw Materials, and Building Product Disclosure and Optimization - Material Ingredients.1 The other options are not always included in Materials and Resources credits. Faucets (option A) and fire suppression systems (option D) are considered as mechanical, electrical, and plumbing components, which are excluded from the scope of Materials and Resources credits unless they are specifically addressed by the credit requirements.1 Furniture (option B) is considered as a non-permanently installed product, which is optional to include in Materials and Resources credits, except for the Building Product Disclosure and Optimization - Material Ingredients credit, where furniture must be included if it is within the project scope.1 Reference: LEED v4 Reference Guide for Building Design and Construction, p. 5791; LEED v4 Reference Guide for Building Design and Construction, p. 5801; LEED v4 Reference Guide for Building Design and Construction, p. 5811; LEED v4 Reference Guide for Building Design and Construction, p. 5821; LEED v4 Reference Guide for Building Design and Construction, p. 5831