Like any red-blooded American, from time to time I find myself needing to crawl through an air duct.  Be it to furtively take pictures of ladies in the restroom, escape when they catch you in the act, or hide from authorities after they call the police, for one reason or another, at some point everyone needs to crawl through an air duct.
What most people don’t realize, however, is that squeezing into a tiny, metallic, coffin-like box is actually quite dangerous.  To better understand the hidden hazards of proper duct locomotion, here are some thoughts to keep in mind before your next adventure above and behind the walls…

•    Before crawling, free your pockets of keys and other potentially castrative devices.
•    Leaving a trail so you can find your entrance grate is always a wise idea.  NOTE: Opt for a ball of twine over breadcrumbs – rats are far less likely to swarm over the scent of thread.
•    Turning off the heat and/or air conditioning before entering the ducts can dramatically increase your odds of survival.
•    Children under 12 must be accompanied by an adult.
•    While most grates are easily unscrewed with a simple coin, very few unscrew from the INSIDE.  As such, it’s wise to keep a blowtorch or other industrial-grade cutting implement on your person to avoid any embarrassing calls to the fire department.
•    Animals other than service animals are forbidden from entering the ducts.
•    If you plan on hosting a party in the air ducts, alerting residents on all sides of the duct is a courteous and well-received gesture.  REMEMBER: Noise travels faster through galvanized sheet metal.
•    No black soled shoes.
•    Stop and look both ways at every duct intersection – you never know when a family of rabid raccoons might suddenly dart out in front of you.
•    When encountering a slower crawler, etiquette dictates you clearly announce which side of the duct you intend to pass them on.
•    Farting in an air duct is strictly prohibited.
•    Before entering, make sure the air filter carries a rating of 8 or higher on the MERV scale (Minimum Efficiency Rating Value).  Mold spores, pet dander, microscopic allergens and other dangerous bacteria can quickly spoil an otherwise delightful excursion through a building’s ventilation system.
•    No roughhousing / horseplay in the ducts.
•    If you suddenly “have to go” and don’t have time to crawl to a restroom, be sure to bury your waste in a small hole after doing your business.  Air ducts are built on respect and courtesy, not just drywall and asbestos-lined sheathing.
•    Infants, elderly persons, and women who are pregnant or plan-to-be pregnant are strongly encouraged to consult with their healthcare professional before entering the air ducts.