CSA ANSI Z83.18:2015 pdf download.Recirculating direct gas-fired industrial air heaters
4.1.5 Non-metallic tubing used in an appliance shall be suitable for the application and the temperatures to which exposed in service and shall not show evidence of deterioration when operated as specified in Clause 5.17, Wall, floor (optional), ceiling, electrical equipment, and wiring temperatures. If the non-metallic tubing is connected to the atmospheric side of a component that can introduce fuel gas into the tubing under a failure condition, the amount of gas released into the tubing shall not exceed a flow rate of 2.5 ft3/hr (19.6 cm3/s) for natural gas, and 1.0 ft3/hr (7.9 cm3/s) for propane gas.
4.1.8 A heater shall have means provided to prevent leaves, papers, or other objects from being picked up from the outside, ignited, and discharged into the heated space. The upper limit of the size of the openings of this means shall be such as to prevent the entrance of a 1%8 in (28.6 mm) diameter rod. The lower limit of the size of the openings in this means shall not prevent the entrance of 1/4 in (6.4 mm) rod.
4.1.10 Thermal or acoustic insulation that may allow smoke to be discharged to the circulating air in the event of a malfunction either shall comply with the requirements for duct coverings and duct linings in the Standard for the Installation of Air Conditioning and Ventilation Systems, ANSI/NFPA 90A, or shall have a flame-spread rating less than 25 and a smoke-developed rating less than 50 when tested in accordance with the Safety Standard for Tests for Surface Burning Characteristics of Building Materials, ANSI/UL 723 or with the Method of Surface Burning Characteristics of Building Materials, NFPA 255.
4.1.11 Insulating materials shall be mechanically or adhesively retained in place. Insulating materials and their internal bonding or adhesive means shall withstand temperatures and air velocities to which subjected in normal operation. If the insulation is such that air impingement on the edges might cause displacement or damage, such edges shall be protected.
4.3.1 All controls shall be accessible for normal servicing and functional adjustment in position and shall be replaceable during normal servicing. Manifold assemblies that permit removal of a control(s) intact shall be considered as complying with this provision. Removal of an access panel or door to provide access to a control compartment is acceptable.
4.3.2 Provision shall be made to permit ready observation of the igniter or pilot and a major portion of the flames of each burner with the heater operating during service or start-up activity. An unsealed observation means with a movable cover shall be acceptable provided it does not exceed 4 in 2 (25.8 cm2). The cover shall be designed and installed with corrosion-resistant mechanism so that it closes automatically when the inspection port is not in use (i.e., positive gravity or spring).CSA ANSI Z83.18 pdf download.