Specifications include, but are not limited to: Each compressor shall be serviced in accordance with The Texas Commission on Fire Protection, NFPA, and the manufacturer’s recommendations using manufacturer approved parts to include but not limited to: 6.1 Each compressor shall have the purification filters changed every 6 months or at any such time that the compressor’s air quality is suspected to be questionable. Each time the purification filter is replaced the service technician shall place a dated marking on the compressor and document it on the written report. 6.2 Each compressor shall have the intake filter removed and a new one installed every 12 months or at any such time the filter shows signs of contaminants or deterioration. Each time the intake filter is replaced the service technician shall place a dated marking on the compressor and document it on the written report.