The employer certifies the WPS, PQR, and WPTR. The employer could assign the task of signing paperwork to the groundskeeper or the vice president of the company. No involvement of a CWI is required by the code.

ASME Sec. IX says the organization shall certify the PQR by
a signature or other means as described in the organization’s
Quality Control System. See QG-102. It's really what's in your QMS. If your manual says a welding inspector can do that then your golden. You have to certify the PQR by a signature. So I don't believe the janitor can do that. My opinion and in my experience , a typical CWI should not be qualifying or signing a PQR unless they have a lot of experience in this field. Should be done by a welding engineer, or a Senior inspector that has a lot of experience in the welding engineering field. Just my opinion. But to be clear, that person is whom your QMS says it is.