How to Build a Shelter in Place Plan

How to Build a Shelter in Place Plan

by Samantha Biggers

While the threat of a genuine chemical, biological, radiological, or nuclear (CBRN) event maybe unlikely, it should never be ruled out.

To this day, global acts of terrorism, industrial accidents, and environmental hazards occur regularly every year. With this in mind, you and your family may very well find yourselves trapped in your own homes. Road could be blocked off, emergency services backed up, and basic services could be rendered useless. Your best option now is to shelter in place. To do so during a CBRN event, you’ll need to educate yourself on what specific risk factors are involved, the proper precautions and procedures to take, the best safety equipment to deploy for protection, and resource management.

This guide will cover how to build a shelter in place plan, specifically the best shelter in place practices so that you can make the right decisions even during the worst possible time.

To learn more about common CBRN threats you may encounter, check out our guide here.


  • 01

    Types of CBRN Threats

  • 02

    PPE Gear for Sheltering in Place

  • 03

    Supply and Resource Management

  • 04


  • 05


Types of CBRN Threats

Not all CBRN threats are the same. Although there are some common supplies and things you should do, it’s important to understand the differences between each scenario so that you can increase your chances of survival and reduce the risk of long-term health effects.


Chemical incidents are by far the most common type of major CBRN event. Chemical threats become problems quickly, and there is rarely much warning, if any. Such an emergency can be caused by something as common as a train derailment or truck accident, or it could be a larger event like an industrial plant catching fire.

How long it takes for a chemical to dissipate or be cleaned up varies depending on the severity of the leak or spill and the weather conditions. Some chemicals are major skin irritants, so even after it is considered safe to go out, cover yourself well just in case you are sensitive to that chemical. Avoid traveling until you know it is safe to do so.

During a chemical emergency, you may be asked to shelter in place and seal off your space until the worst of the danger has passed.


During a radiation emergency, it’s critical to stay inside. Whatever you can put between you and the fallout will limited your exposure to radioactive dust, particles and the worst of all: ionized radiation. Gamma rays can pierce through virtually anything aside from thick layers of solid materials. That’s why those who want to be the most prepared have bunkers. Most people don’t have access to a bunker, so they need to go with the next best thing.

A concrete basement or underground parking garage will help protect you from nuclear fallout and may offer some protection from a blast. Underground structures are definitely best.

If you have warning of a nuclear event or that fallout is headed in your direction, seek cover immediately. If you can’t go into a basement or subterranean space, at least find a sturdy building and shelter in the center of it away from doors, windows, etc.

If you have time, it’s best to make sure all exterior windows and doors are closed before you move to the center to take shelter.

The CDC recommends staying inside for 24 hours to eliminate the greatest danger from nuclear fallout.

To learn more about surviving nuclear attacks, read our 4 Key Factors to Surviving Nuclear War and 4 Things You Need to Know to Survive Nuclear Fallout guides.


Only eat foods that have been in a sealed container or in a fridge. It’s best to wipe the outside of any food containers before opening them unless they have been in a sealed cabinet or pantry. Throw any wet rags or paper towels used to wipe containers into a garbage bag and seal the bag to minimize the risk of exposure.

Radioactive material can be passed through breastmilk. If you have an infant and believe you have been exposed to radioactivity, you should stop breastfeeding and use powdered formula mixed with bottled water or even better, use pre-mixed formula from a sealed bottle. If you have frozen or refrigerated breast milk, you can use that.


Do not drink tap water until you know it’s safe to do so. Only drink bottled water or other drinks that come in a container. As with sealed food, wipe the outside before consuming. Water or drinks in your fridge are safe to consume.


Water in your hot water heater or toilet is safe to use for hygienic purposes. Although you should not consume tap water, any contamination in groundwater will be diluted enough that you can use it to decontaminate surfaces and objects. Washing up with tap water is a still a far better solution than letting radioactive dust stay on your skin if you’ve been exposed.

How to Seal Off a Room

While it may seem like a good idea to seal off windows, doors, or air gaps, it’s important not to seal it too well. There have been incidents where people sealed off the rooms they were sheltering in place in so well that they died from lack of oxygen. Sealing off a space may be good for a short period of time but knowing how long is safe is tricky. Always listen to radios or other emergency services for guidance on what to do. If no instructions are given, common sense dictates that you should seal off rooms only for short periods of time.

Choose the room in your home or office building that has the fewest windows, is on the highest floor, and has few doors. Designate this your safe room and make sure everyone in your family or at your workplace knows where to go.

What You Need

  • Duct tape or ChemTape

  • Plastic sheeting

  • Scissors

  • Towels

  • Pre-cut plastic sheets, one per window (make these ahead of time)

Assemble a kit with these materials and stash it in the designated safe room.

The CDC recommends practicing sealing all the major air outlets and intakes in your chosen room. Practice is a good idea so that you can take care of things faster and with less errors when an event actually occurs and you’re under stress.

Seal off the following and make sure to double check for any vents that you may be missing.

  • Doors and windows

  • Window air conditioners

  • Bathroom and kitchen exhaust fans

  • Stove and dryer vents

Make sure that safe rooms are always well stocked with water and food supplies or have supplies on hand that can be easily grabbed and stashed in the room while it is being sealed off.

Use whatever communications method available to stay informed of emergency alerts. If cell phones are working, text alerts may be sent out as part of the emergency alert system. Keeping an emergency radio on hand is a good idea if other communications fail.

Sheltering in place and being sealed in a room without windows or with very few windows can be terrifying for some. If someone in your group is claustrophobic, it is critical that everyone remains as calm as possible. Panic is often contagious during a scary situation.

Is there a good way to know if oxygen levels are too low in a room?

(Image source: Image courtesy of Músculos Espartanos)

It’s very difficult to know how much oxygen is left at any given point after a room has been sealed. One way to avoid a dangerous situation is to use pulse oximeters. During the COVID-19 pandemic, many people invested in these inexpensive oxygen monitors that clip on a fingertip and run on batteries. Having several of these in your safe room kit would allow you to monitor blood oxygen levels. Any oxygen level below 88% is dangerous to major organs. Since people vary in size, using a pulse oximeter on one of the bigger and one of the smaller people in the room is a good way to keep tabs on the oxygen level. At 90% or so, it’s best to allow some fresh air in even if emergency services have not advised it. The last thing you want is people suffering organ damage or passing out from lack of air.

Bunkers and fallout shelters

Recently, there has been enormous demand for fallout shelters and bunkers from manufacturers such as Atlas Survival Shelters in Texas. While certainly having this level of protection would be ideal, one should understand that this is a complicated task that requires extensive planning, attention to detail, and a decent budget. Bunkers must have good airflow and ventilation systems. Without a well-designed system, a bunker can be deadly.

You also have to decide what to put in a bunker. Unless you’re extremely wealthy, your bunker will be very compact, especially if you are sharing it. There won’t be room for much beyond the supplies needed to sustain you for a short to medium period.

If you’re interested in a bunker, I recommend researching pre-built options unless you’re ready to take on a serious building project. Hiring a company to install a bunker is difficult to do with any degree of stealth. A big trailer delivering even a small bunker will get some attention from anyone that happens to see it. You’ll also need some heavy equipment work to bury it properly.

After that, there’s a decent chance that your neighbors will know that you have a bunker. That means that during an emergency, they are likely to seek help from you, even if they bring nothing to the table.

This lack of secrecy is one of the main reasons people decide to build their own fallout shelters. Again, many find it a lot harder than it seems. Do your research, and consider the pros and cons of a bunker before taking on any projects.

Remember, bunkers protect you and get you through an emergency. They don’t have to be set up like a luxury hotel room to do that. The important thing is having your bunker set up to meet your basic needs while keeping you safe.

For additional information on how to build a shelter to survive nuclear war, I highly recommend the book Nuclear War Survival Skills: Lifesaving Nuclear Facts and Self-Help Instructions.

It’s possible to build an underground shelter using very basic materials. Any dirt or other materials between you and the fallout will increase your chances of survival.


Many people think that biological threats remain viable for a long period of time or mutate into other forms. That’s not always the case. Left alone, a man-made biological threat is likely to break down and be rendered harmless in a relatively short period of time. Consider how UV light destroys bacteria and viruses in 10 minutes or less.

Man-made biological threats are more unstable than naturally occurring bacteria and viruses because natural born variants develop and evolve slowly to survive in the natural world. They are part of nature itself. Man-made viruses and bacteria are created in laboratory conditions in short periods of time. With no previous exposure to the natural world, they break down quickly and often turn into something less harmful.

It doesn't benefit a bacteria or virus to kill its host before it can spread to others. This is why some diseases spread rapidly. Ebola is a good example of a disease that acts quickly on the host. It is not slow acting enough to allow for unknown spread over a great distance.

However, it’s important to not underestimate how long you need to shelter in place. When you emerge, you should wear personal protective gear (PPE) just in case. There may still be a low-level threat or other threats that are unknown to you. Understand that the primary way for viruses and bacteria to spread is through the nose and mouth, whether that be from sneezing, coughing, hand contact, or consumption of food and water. Sanitizing surfaces and donning appropriately rated masks such as N95s or half face respirators with particle filters are a must.

Ideally, you’ll be given the okay by emergency services, but if you’re not and a long time has passed in a severe situation, you may have to use your judgment to decide when it is okay to stop sheltering in place.

Fortifying In Advance

Knowing how to build a shelter in place plan begins with getting ahead of the problem. Since attacks or accidents may happen quickly, the more advance preparation, the better.

Remember that during any emergency, it’s difficult to think clearly so that you do things in the correct order. This is especially true if you also have family and pets to worry about. Know what room you’ll gather in if there’s a disaster. Start staging supplies in that room as soon as you know of a potential threat. For example, if you live in an industrial area, it’s a good idea to stash some basic PPE items and stage them for easy use.

PPE Gear for Sheltering in Place

As stated before, it is vitally important to not only have high quality CBRN survival equipment but to also have them ready to go when needed. It’s not enough to know how to build a shelter, it’s also just as important to make preparations for individual protection. These include the following:

Gas masks

A full face gas mask offers the most complete protection because it covers your eyes, so you don’t have to worry about separate goggles. The MIRA Safety CM-6M Tactical Gas Mask is among the best in class for CBRN agents. It features a full face panoramic visor for unobstructed vision, bromobutyl rubber for high resistance against blistering chemical agents, and can take 40mm NATO filters.

(Image source: Image courtesy of Blue Line Syndicate Group and The Iridium Group)

If you have children, be sure to have a respirator suitable for their age and size, such as the CM-3M or the MD-1 Children’s Gas Mask. These are among the only genuine CBRN rated gas masks available for children and are the perfect PPE gear for your family.

PAPR (Powered Air-Purifying Respirator)

A PAPR or powered, air-purifying respirator, is a must have field upgrade for your gas mask. This device acts a blower that provides constant air flow within the mask, greatly reducing breathing resistance and cools the body down. If a child doesn’t have the lung capacity to blow up a balloon on their own, they need a PAPR.

Similarly, adults with breathing problems or limited lung capacity may be able to use a gas mask as long as they have a PAPR unit such as the MIRA Safety MB-90. Even adults with great lung capacity and endurance will breathe more comfortably with a PAPR when physically exerting themselves.

Gas Mask Filters

Your gas mask is only as good as the filter it is attached to. For CBRN threats, you’ll naturally need a CBRN rated filter, like the MIRA Safety NBC-77 SOF filter. This cartridge is among the highest grade of filters available today, as it houses a particle filter component, gas filter, and even a reactor component.

This means this one filter will protect against particulates from viruses, bacteria, dust, in addition to toxic industrial chemicals and chemical warfare agents as well as radioactive iodide. Understand that not all respirator cartridges are designed for CBRN threats and it is important to find the right tool for the right job. If you use the NBC-77 SOF, you essentially have a near catch all solution.


Should the worst happen and your home becomes completely saturated with CBRN agents, you’ll need a full-bodied solution for the entire family. Luckily, the MIRA Safety HAZ-Suit along with its HAZ-Gloves and CBRN Overboots are the perfect solution. The suit itself is made from a robust, puncture-resistant film composite and tested to protect against over 125 chemicals, including chemical warfare agents and toxic industrial chemicals. The HAZ-Gloves and CBRN Overboots are both made from heavy-duty butyl rubber, material similar to the gas mask, that is specifically designed to resist harmful chemical gases. Combine this entire kit with a gas mask, filter, and ChemTape, you will have a very effective CBRN solution.

(Image source: Image courtesy of Blue Line Syndicate Group)


In a shelter in place scenario, sealing off the cracks and openings of your home may be required. Duct tape is great tool but an even better solution is the use of ChemTape. This specialized tape is rated to resist against chemical warfare agents such as sarin, VX, and mustard gas. When wearing your HAZMAT suit, this is used to seal off the seams at the wrist, ankle, and around the gas mask. When you’re in the safety of your own home, as stated above, you would use this to seal off windows, doors, and other openings if needed.

(Image source: Image courtesy of Blue Line Syndicate Group)

Supply and Resource Management

Even if a major CBRN threat has largely passed over your area, other problems and dangers can still arise. Consider that resources will likely be stripped clean in local stores or main exit routes could be congested. Here’s a short list of supplies you should keep at home to provide for your needs during CBRN events and other emergencies.

Food and Water

People often ask how much food they should keep on hand in case of an emergency. There is no one-size-fits-all answer. At least six months’ worth is ideal, but not everyone has that much storage space. However, freeze-dried food takes up much less space and is designed to be stored up to 25 years. Even if you’re short on space, keeping one or two months worth of food on hand should be manageable with a little planning. That much food buys enough time for you to figure out your next move.

Water storage is tricky. Although the news features stories of people stockpiling massive amounts of bottled water, practically no one has the space to store enough water to meet all of their family’s needs for more than a week. Keep at least 72 hours of water stored, but also invest in a good gravity-fed water filter such as the Sawyer Mini with a hydration bag.

Medical Supplies and Prescription Medications

Sheltering in place essentially means that you are your own first responder. So you need a medical kit that’s large enough to meet the needs of everyone living in your home. There are some excellent comprehensive medical bags you can purchase and then add any supplies you feel are missing. cIf anyone in your family relies on prescription medication, always refill their prescriptions as soon as possible. Most doctors have no problem writing a script for a 90-day supply if it’s not a controlled substance.

Blankets and Extra Clothing

Sheltering in place may mean sealing off vents, at least for a while. You may lose the ability to heat your home, so keep items on hand to stay warm. Sleeping bags, emergency Bivvy bags, emergency blankets, and warm clothing are all good options. USB-powered hand warmers are wonderful if you have electricity or a back-up power supply in case of a grid down scenario during a CBRN event.

Curiosity is dangerous, stay put!

Sheltering in place can be scary, more so for some than others. Additionally, staying in one place gets boring, especially if there’s nothing to entertain yourself with. The urge to know what’s going on and see things for yourself is strong, but it’s critical for your safety and well-being and that of others that you don’t break a shelter-in-place order too soon.


How can I convince my workplace to create a shelter-in-place plan?
How can I be better prepared for a CBRN event when away from home?


During a CBRN event, knowing how to build a shelter in place plan could be the difference between life or death. One should not only plan to do so but also plan for surviving for more extended periods of time. Knowing what to do ahead of time ensures that you can act quickly and have the best odds of survival and reduce the potential for long-term health effects. While having some gear is a great idea, knowing how you react to a situation is critical. Staying calm and taking orderly and decisive action is the best way to protect yourself during a CBRN event.