Fragment-, overpressure-, radiation-, and toxic-resistant emergency safety shelter

Abstract

A modular safety shelter provides protection from fragment, overpressure, radiation, and toxic hazards through a combination of physical design of modular segments, of joint seals between modular segments, of door assemblies, and of HVAC control systems. The modular shelter is formed of two or more prefabricated concrete modular segments each including a built-in foundation, roof, and side walls, and a prefabricated concrete vestibule segment providing an airlock-like access to the shelter. The prefabricated modular segments and vestibule segment are transported to a site and assembled to each other on-site to provide a fully enclosed space within the modular shelter. A multi-layer joint seal is formed between adjacent modular segments to prevent ingress of toxic, flammable, or thermal hazards. An integrated HVAC controller monitors toxic or flammable hazards outside and inside of the shelter, and controls HVAC systems to minimize spread of contaminants upon detecting a hazard.

1 . (canceled) 
     
     
         2 . A modular shelter, comprising:
 two or more prefabricated modular segments each including a built-in foundation, a built-in roof, and one or more side walls extending between the built-in foundation and roof,   wherein the built-in foundation, built-in roof, and one or more side walls of the modular segments are made of concrete; and   a joint seal sealing a plurality of joints between the two or more prefabricated modular segments,   wherein the joint seal comprises a thermally resistant backer rod disposed in the joint between the segments, a fire resistant intumescent sealant disposed in the joint to a side of the thermally resistant backer rod facing an exterior of the modular shelter, and a gas or water sealant disposed in the joint to a side of the fire resistant intumescent sealant facing the exterior of the modular shelter.   
     
     
         3 . The modular shelter of  claim 2 , further comprising at least one prefabricated vestibule segment including a built-in foundation, a built-in roof, at least three side walls extending between the built-in foundation and roof all made of concrete, and external and interior doors disposed in respective side walls and respectively opening towards the exterior of the modular shelter and an interior of the vestibule segment. 
     
     
         4 . The modular shelter of  claim 3 , wherein the walls and roof of the two or more prefabricated modular segments and the at least one prefabricated vestibule segment are constructed with monolithic beams and columns. 
     
     
         5 . The modular shelter of  claim 3 , wherein the at least one prefabricated vestibule segment extends beyond boundaries of the two or more prefabricated modular segments. 
     
     
         6 . The modular shelter of  claim 3 , wherein the at least one prefabricated vestibule segment includes an external door assembly including:
 a door frame, having an opening, mounted in an opening of the at least one prefabricated vestibule segment and welded to steel plates embedded in a side wall of the vestibule segment; and   the external door,   wherein the external door comprises a multi-layer door panel configured to fit in the opening of the door frame when the external door is closed, a blast-resistant door inner-frame having two vertical members and a plurality of cross-members extending between the two vertical members, a first thermal insulation layer disposed to substantially fill spaces between the vertical members and the cross-members of the door inner-frame, a second thermal insulation layer disposed between the door inner-frame and the exterior of the modular shelter, and a steel panel mounted to the exterior of the blast-resistant door inner-frame.   
     
     
         7 . The modular shelter of  claim 3 , wherein the at least one prefabricated vestibule segment includes an external door assembly including:
 a door frame, having an opening, mounted in an opening of the at least one prefabricated vestibule segment and welded to steel plates embedded in a side wall of the vestibule segment; and   the external door comprising:
 a steel exterior door panel configured to fit in the opening of the door frame when the external door is closed, 
 a heat resistant gasket providing a seal against penetration of gases, disposed between the door frame and the multi-layer external door along an entire periphery of the opening; 
 an interior cladding; 
 a blast-resistant door inner-frame mounted to an exterior of the interior cladding, the inner-frame having two vertical members, a top cross member extending between the two vertical members at a top of the vertical members, a bottom cross member extending between the two vertical members at a bottom of the vertical members, and a plurality of cross-members arranged between the top cross member and the bottom cross member extending between the two vertical members; 
 a first thermal insulation layer disposed to substantially fill spaces between the vertical members and the cross-members of the door inner-frame, 
 wherein the steel exterior door panel is mounted to an exterior of the blast-resistant door inner-frame; and 
 a second thermal insulation layer disposed between the blast-resistant door inner-frame and the steel exterior door panel. 
   
     
     
         8 . The modular shelter of  claim 7 , wherein the interior cladding and the steel exterior door panel include ⅛-inch thick cold-formed steel sheet. 
     
     
         9 . The modular shelter of  claim 7 , wherein the vertical members and the cross-members of the blast-resistant door inner-frame include hollow structural section (HSS) steel-tube members that are welded to each other. 
     
     
         10 . The modular shelter of  claim 7 , wherein the first thermal insulation layer is formed of a mineral wool. 
     
     
         11 . The modular shelter of  claim 7 , wherein the heat resistant gasket includes two gaskets,
 wherein a first outermost gasket includes a heat resistant silicone gasket, and a second gasket is a thermally resistant glass fiber gasket.   
     
     
         12 . The modular shelter of  claim 3 , further comprising:
 a joint seal sealing a plurality of joints between any of the two or more prefabricated modular segments and the vestibule segment to limit air ingress from outside to less than 0.1 air changes per hour.   
     
     
         13 . The modular shelter of  claim 2 , wherein each side wall of each of the two or more prefabricated modular segments is configured to deflect no more than 1 inch in response to a blast overpressure of up to 8 psig. 
     
     
         14 . The modular shelter of  claim 2 , further comprising:
 a controller for a heating, ventilation, and/or air conditioning (HVAC) system configured to provide air circulation to an interior of the shelter,   wherein the controller comprises a gas detector interface for receiving a measurement of a toxic or flammable gas concentration at a location exterior to the shelter, and   the controller is configured to control shutdown of air circulation provided by the HVAC system upon the measured toxic or flammable gas concentration exceeding a threshold concentration.   
     
     
         15 . The modular shelter of  claim 14 , wherein the controller is further configured to actuate a release of fresh air from a pressurized source into an interior of the shelter upon determining that the measured toxic or flammable gas concentration at the location exterior to the shelter exceeds the threshold concentration. 
     
     
         16 . The modular shelter of  claim 14 , wherein the controller is further configured to monitor a concentration of toxic or flammable gas inside the shelter and provides data to site security and management upon determining that the toxic or flammable gas concentration inside the shelter is at an unsafe level. 
     
     
         17 . The modular shelter of  claim 14 , wherein the modular shelter insulates against a heat flux density of 100 kW/m 2  applied for 1 hour to an exterior wall such that air temperature in an interior of the shelter does not exceed 140° F. 
     
     
         18 . The modular shelter of  claim 2 , further comprising a door assembly including:
 a door frame, having an opening, and welded to steel plates embedded in a wall of the modular shelter; and   an external door comprising a multi-layer door panel configured to fit in the opening of the door frame when the external door is closed, and including a blast-resistant door inner-frame having two vertical members and a plurality of cross-members extending between the two vertical members, a first thermal insulation layer disposed to substantially fill spaces between the vertical members and the cross-members of the door inner-frame, a second thermal insulation layer disposed between the door inner-frame and the exterior of the modular shelter, and a steel panel mounted to the exterior of the blast-resistant door inner-frame.   
     
     
         19 . The modular shelter of  claim 2 , further comprising an external door assembly including:
 a door frame, having an opening, mounted in an opening of the shelter and welded to steel plates embedded in a wall of the shelter; and   a multi-layer external door comprising:
 a steel exterior door panel configured to fit in the opening of the door frame when the external door is closed, 
 a heat resistant gasket providing a seal against penetration of gases, disposed between the door frame and the multi-layer external door along an entire periphery of the opening; 
 an interior cladding; 
 a blast-resistant door inner-frame mounted to an exterior of the interior cladding, the inner-frame having two vertical members, a top cross member extending between the two vertical members at a top of the vertical members, a bottom cross member extending between the two vertical members at a bottom of the vertical members, and a plurality of cross-members arranged between the top cross member and the bottom cross member extending between the two vertical members; 
 a first thermal insulation layer disposed to substantially fill spaces between the vertical members and the cross-members of the door inner-frame, 
 wherein the steel exterior door panel is mounted to an exterior of the blast-resistant door inner-frame; and 
 a second thermal insulation layer disposed between the blast-resistant door inner-frame and the steel exterior door panel. 
   
     
     
         20 . The modular shelter of  claim 19 , wherein:
 the interior cladding and the steel panel include ⅛-inch thick cold-formed steel sheet, and   the vertical members and the cross-members of the blast-resistant door inner-frame include hollow structural section (HSS) steel-tube members that are welded to each other.   
     
     
         21 . The modular shelter of  claim 19 , wherein the heat resistant gasket includes two gaskets,
 wherein a first outermost gasket includes a heat resistant silicone gasket, and a second gasket is a thermally resistant glass fiber gasket.