Options to consider: a unit with multiple entrances for quick access; adequate seating; above ground or below ground.
SafeShed / SafeRoom Option: Above ground shelter. There are no stairs to gain entry into the unit, so it is elderly and wheel chair accessible. We use the same guidelines to build a larger unit that we follow to build our safe room unit. Original Safe room unit is a tested unit at Texas Tech. With a community size unit, we follow our original design method while adding more of the 4 inch channel to protect you from falling debris. This type of unit would be built in shop and delivered to your site. It would be anchored to a concrete slab (that you have in place, provided it meets safety expectations or a slab that is prepared for it to set and anchor upon) Once the siding is on the Safe Shed it looks very attractive. The siding color can be incorporated into the rest of the building that it is going to be close to.
Underground Option: Underground unit will have stairs into unit, body of unit is fully beneath ground. If it is a larger unit, you may want to consider having 2 entries into the unit to expedite getting people inside quickly. This unit typically has the 30" X 5'0 hatch entry with 8 steps into the unit. Once you are off the bottom step, you are in an open room. If you have a large number of people to accommodate, you can also consider having 2, 3, or more units put on the site of your business in various locations or close together.
In considering the size of the shelter you would need, FEMA offers a recommendation for your consideration of this. Their recommendations are as follows:
For example, a 6 X 24 (144 sq. ft.) would accommodate 24 adults seated. We find that typically more people can fit when a situation of need arises.
All will agree, our weather has become so unpredictable that there is a desperate need for shelters at our places of work or at any facility which we have to visit or take our loved ones. Who of us wouldn’t feel better about going to such a place that takes this into consideration? Such facilities as Nursing Homes, Medical Facilities, Day Care Centers, Schools, etc. could benefit from having a storm shelter. Consider --Which would be a more desirable place to leave your child? a day care facility that has a plan of action and a storm shelter to be used or a day care that has a plan of action but no shelter to be used.