Vacuum water closets covered by this CID are intended for use in VCHT systems for new construction ships or as stock replacements for water closets currently installed on existing ships. When acquiring water closets for replacement purposes, the contracting activity should ensure that interface requirements are specified (see 7.5) for water and discharge connections that are compatible with the water closet being replaced to avoid the need for costly ship modifications. Acquisition for new construction allows for more latitude in water closet dimensions and interface requirements, enabling more suppliers to bid, thereby increasing competition. Originally installed water closets may no longer be in production and specifying special mounting dimensions and interface connections for exact replacement should be avoided. Consideration should be given to making minor shipboard changes instead of specifying special dimensions. The availability of supplier-furnished retrofit kits should be investigated, as specified (see 7.5). Water and discharge connections location and mounting bolt patterns generally are not an issue for new construction.