install hvac equipment in arizona. i work at a company that installs duct work in mobile homes that have been around for a while there is no codes trailers have no room to move some have 9 inches to crawl around in and we put pipe that is 18 inches crawling around alone is hard enough let alone pulling duct work if that is bad enough you dont know if there is rattlesnakes scorpions or brown reclouse spiders under the trailers. thats just part of some of the installs we go in attics also that the temps can get up to 150 degrees fiberglass insulation and dirt u start coughing and most of the roof pitches are 3/12 not much room to move pretty much crawling in the attic trying to stay on the rafters working with 18 inch pipe