Reference Plane 2 : The plane that is 102. 5 mm down from the top of the head and parallel to the basic plane on an ISO size J headform. NFPA 1971, 2000 ed
National Fire Protection Association, Illustrated Dictionary of Fire Service Terms, Jones & Bartlett Publishers, MA. USA 2006. https://books.google.com.kw/books?id=W0WIRa3Gl4QC& printsec=frontcover&source=gbs_ge_summary_r&cad=0# v=onepage&q&f=false, (Fr Srvc - Amer) {141}
NFPA 1976 Standard on Protective Ensemble for Proximity Fire Fighting, 2000 ed. https://www.nfpa.org/assets/files/AboutTheCodes/19 76/TIA1976-00-1.pdf, (Std: Prot Ens for Proximity Fr Fight - Amer) {430 NFC}