Building a School Safe Room with Bautex Blocks

Tor­na­do-resis­tant safe rooms are cru­cial in the Unit­ed States where an aver­age of 1253 tor­na­does occur annu­al­ly, pro­duc­ing wind speeds up to 200 mph or more. Safe rooms in schools are espe­cial­ly impor­tant because our chil­dren count on us to pro­tect them. In 2013, the need for safe rooms in schools became trag­i­cal­ly appar­ent. A tor­na­do with winds of 210 mph hit and destroyed two ele­men­tary schools in Moore, Okla­homa — killing sev­en chil­dren. Struc­tur­al defi­cien­cies in the schools were blamed for the build­ings col­laps­ing. Tor­na­do-proof safe rooms in the schools could have pre­vent­ed this loss of life.

Since 2015, the Inter­na­tion­al Build­ing Code (IBC) and the Inter­na­tion­al Exist­ing Build­ing Code (IEBC) have required storm shel­ters (safe rooms) in K‑12 school build­ings (Edu­ca­tion­al Group E). These spec­i­fi­ca­tions apply to schools with at least 50 occu­pants and locat­ed in areas with shel­ter design wind speeds of 250 mph, as spec­i­fied by the Inter­na­tion­al Code Coun­cil (ICC) ICC-500, Fig­ure 304.2(1). The ICC-500 is the ICC/NSSA stan­dard for the design and con­struc­tion of storm shel­ters. Its pur­pose is to pro­tect the occu­pants in build­ings from dan­ger­ous winds and fly­ing debris caused by hur­ri­canes and tor­na­dos. The IBC along with the Inter­na­tion­al Res­i­den­tial Code (IRC), site the ICC-500 as the gov­ern­ing stan­dard for the design and con­struc­tion of storm shel­ters. There are sev­er­al spe­cif­ic fea­tures of a safe room required by the ICC-500.

  • The safe room must be large enough to hold all the occu­pants of the build­ing
  • The safe room must with­stand a direct hit from a tor­na­do with wind speeds of 250 mph
  • A safe room’s walls must with­stand a debris mis­sile impact of a 15-pound, 2‑inch X 4‑inch shot at 100 mph
  • Roofs of a safe room must with­stand an impact of a 15-pound, 2‑inch X 4‑inch shot at 67 mph

Besides a sol­id out­er struc­ture, the design of a safe room must include sev­er­al oth­er fea­tures.

  • HVAC and MEP sys­tems
  • Toi­lets and hand wash sys­tems which are inde­pen­dent of city sys­tems.
  • Prop­er ven­ti­la­tion and illu­mi­na­tion

The Fed­er­al Emer­gency Man­age­ment Asso­ci­a­tion guide­lines (FEMA P‑320 and FEMA 361), which also use ICC-500 as a ref­er­enced stan­dard, also spec­i­fy require­ments for a safe room. The FEMA guide­lines, how­ev­er, are con­sid­ered slight­ly more con­ser­v­a­tive than the IBC and IRC require­ments.

  • Safe rooms must be anchored to the build­ing’s foun­da­tion to resist over­turn­ing and uplift
  • A safe room must have a con­tin­u­ous load path that resists lat­er­al and uplift loads dur­ing high winds
  • The roof, open­ings, and walls of a safe room must resist per­fo­ra­tion by wind­borne debris
  • The walls of the safe room are inde­pen­dent of the rest of the build­ing

Constructing a School Safe Room

A school safe room must be designed and built in com­pli­ance with the stan­dards man­dat­ed by the IBC, IEBC, and FEMA. Safe rooms must main­tain their integri­ty dur­ing the high wind forces of a tor­na­do or hur­ri­cane. Also, the mate­ri­als used for the entire enve­lope of the safe room must com­bat struc­tur­al dam­age by wind­borne debris. Final­ly, the safe room(s) must be large enough to hold every­one in the school and be locat­ed either with­in the school or no more than 1000 feet from at least one of the school’s exte­ri­or doors. A safe room can be an assigned sin­gle use space or a mul­ti­ple use space like a gym­na­si­um, cafe­te­ria, or oth­er large com­mu­ni­ty space. Safe rooms built to codes and stan­dards will pro­vide stu­dents, teach­ers, and oth­ers the best pro­tec­tion dur­ing a dan­ger­ous tor­na­do or hur­ri­cane event.

Components in the Design of a School Safe Room

A school save room designed with a strong con­tin­u­ous load path should main­tain its struc­tur­al integri­ty dur­ing a severe wind event. A con­tin­u­ous load path ensures that the con­nec­tions between the roof, walls, and foun­da­tion will have the strength to resist the ver­ti­cal and lat­er­al loads dur­ing severe weath­er. The com­po­nents of a safe room must also resist the impact of wind-borne debris, flood loads, and buoy­an­cy forces.

The Walls of A School Safe Room

The walls are the main com­po­nent of the safe room that resists the lat­er­al-loads (hor­i­zon­tal wind forces). They also are bearing/​shear walls. The wind forces on the roof, trans­fer to the walls. The walls then trans­fer these forces to the foun­da­tion, and ulti­mate­ly to the ground. The walls must also have the strength to sup­port the roof. An ide­al prod­uct for safe room con­struc­tion is the Bau­tex™ Block Wall Assem­bly. The Bau­tex Blocks have the con­tin­u­ous load path need­ed to resist the strongest winds. Bau­tex Blocks meet the Fed­er­al Emer­gency Man­age­ment Agency FEMA 320 and FEMA 361 guide­lines in storm zones with wind speeds up to 250 mph.

Foundation and Anchoring Criteria for Safe Rooms

The foun­da­tion of a safe room receives the loads from of the walls and directs the forces into the ground. The design and anchor­ing of the foun­da­tion must fol­low the cri­te­ria in FEMA P‑361, as spec­i­fied by the ICC-500. The ICC-500 (Sec­tion 308.1.1.2) man­dates that the design of slab-on-grade foun­da­tions be in accor­dance with ICC-500. Dur­ing extreme wind events, the foun­da­tion of a safe room must resist uplift, over­turn­ing, and slid­ing forces. Slabs must have a min­i­mum thick­ness of 3.5‑inches with a min­i­mum of 6‑inch X 6‑inch, W 1.4‑inch X W 1.4‑inch weld­ed wire rein­force­ment. Or the slabs can have num­ber four bars spaced at a max­i­mum of 18-inch­es on cen­ter in two per­pen­dic­u­lar direc­tions.

The Roof and Doors of a Safe Room

A safe room roof must be secure­ly and suf­fi­cient­ly con­nect­ed to the walls so as to with­stand the wind forces of a tor­na­do. Roofs of a safe room must be built to resist the impact of a 15-pound 2‑inch X 4‑inch shot at 67 mph. The roofs must also be imper­me­able to water. Rein­forced con­crete roofs, like con­crete walls, can with­stand the wind forces, attacks by debris caused by a tor­na­do, and when prop­er­ly installed are water­proof.

The doors of a safe room must with­stand wind forces and fly­ing debris. Doors used in safe rooms should have doc­u­ment­ed proof that they are com­pli­ant with the most cur­rent ver­sion of FEMA P‑361 and FEMA P‑320 or the ICC 500 for tor­na­do wind speed of 250 mph.

A Safe Room Must Protect Against Flying Debris During High Wind Events

The entire enve­lope of school safe room must pro­tect the room’s occu­pants from fly­ing debris dur­ing tor­na­does and hur­ri­canes. A study by Texas Tech Uni­ver­si­ty com­pared the effect of wind-gen­er­at­ed debris against walls con­struct­ed of ply­wood, met­al com­bi­na­tions, fin­ished con­crete mason­ry unit (CMU), rein­forced con­crete, and oth­ers. The study proved that con­crete walls for a safe room are the best choice for pro­tect­ing occu­pants from fly­ing debris. Bau­tex Block Wall Assembly’s insu­lat­ed con­crete block has the strength and mass to com­bat the impact to wind dri­ven debris at speeds greater than 100 mph. The Bau­tex Blocks meets or exceeds the fol­low­ing ICC-500 FEMA stan­dards for debris impact.

  • Series 1 FEMA 320361 Bau­tex Block Pan­el with Brick Veneer.
  • Series 2 FEMA 320361 Bau­tex Block Pan­el with CMU Block Veneer.
  • Test pro­jec­tile 15 lb. wood­en 2‑inch X 4‑inch pro­pelled at 100 mph.

A safe room is cru­cial for the pro­tec­tion of those that work and study in a school, par­tic­u­lar­ly in tor­na­do-prone regions like Tor­na­do Alley. After the announce­ment of a tor­na­do warn­ing, occu­pants of a school have on aver­age 13 min­utes to seek shel­ter from the up to 250 mph winds and the large fly­ing debris caused by a tor­na­do. A school safe room con­struct­ed with Bau­tex Blocks will pro­tect chil­dren and teach­ers in a school by with­stand­ing the winds and dan­ger­ous debris of the strongest tor­na­do.