If all new cylinders must be keyed into an existing security system, which specification type should be used for the door hardware?

• A. Descriptive specifications
• B. Reference specifications
• C. Performance specifications
• D. Proprietary specifications

Answer: (D)

When you need to guarantee that newly installed door cylinders will work exactly with an existing security system, you lock the requirement to a single product path. This is what a proprietary specification does: it mandates a particular manufacturer or product line so there are no substitutions. By specifying a specific cylinder family designed to integrate with the current keying system, you ensure compatibility of the keyway, cores, and pinning, and you can coordinate maintenance and rekeying within that system.

Other specification types describe the work in general terms, point to standards or catalogs, or define performance criteria without forcing the exact product. Those approaches can allow substitutions that might not fit the existing security setup, risking incompatibility or gaps in the keying scheme. So, for ensuring the new cylinders are keyed into the existing system, a proprietary specification is the appropriate choice.