Section 28-113.3.3. Retesting of materials

All materials tested and accepted
  for use shall be subject to periodic  retesting  as  determined  by  the
  commissioner,  and  any  material  that  upon  retesting is found not to
  comply with the code requirements or the requirements set forth  in  the
  approval  of  such  material  shall  cease  to be acceptable for the use
  intended. During the period for such  retesting,  the  commissioner  may
  require  the  use  of  such material to be restricted or discontinued if
  necessary to secure safety.