I am with an airline in Canada and the fire prevention officer in 1 of our locations has advised we must change all of our ABC portable fire extinguishers mounted on mobile equipment to Purple K type. The individual is referring to NFPA-410 as the basis for this requirement. We have reviewed NFPA-410 and see nothing in this document indicating Purple K extinguishers are required on our equipment. Can you advise if there is anything in NFPA indicating we must have Purple K or anything indicating we must not use ABC extinguishers on mobile airport equipment? This 1 location represents over 100 portable extinguishers and we have 42 other locations to consider as well so would really like to understand requirements before acting. Thanks in advance.