Airburst is something that behooves one to get a blast door to their shelter, complete with air vent connected to a reservoir of non-flammable liquid as a buffe

Airburst is something that behooves one to get a blast door to their shelter, complete with air vent connected to a reservoir of non-flammable liquid as a buffer. If outside the wood-constructed residential air blast range (16.4 miles for airburst 20Mton load), a simple plywood-reinforced wooden door will do. Chinese Civil Defense outlines using wooden poles in the A-frame over 3' deep trench then cover with 3-feet dirt. Only need to shut the door once you see a "spotlight" shining your way as its 2.4 seconds from light to the blast wave for an airburst, longer as you're further way.