Home Glossary Proprietary specification Glossary Proprietary specification By Deviation Check Editorial Team. Short answer A spec that names specific manufacturers or products. An open proprietary spec allows or-equal products, a closed one allows only the products it lists, and a sole-source spec names a single product with no alternatives. Related terms Prescriptive specificationOr equal Browse the full glossary, the CSI division guides, or learn how submittal review works. Then run a review. View this page as Markdown for LLMs and note-taking.