Weather Resistant 2 : Sufficiently protected to prevent the penetration of rain, snow, and wind-driven sand, dirt, or dust under all operating conditions. NFPA 414, 2001 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}
