AT/FP DESIGN STANDARDS AT/FP has gained prominence in recent years, and has been a developing design issue for military and other federal projects. TWO APPROACHES: DoD through the UFC s (Unified Facilities Criteria) GSA through the ISC s (Interagency Security Committee)
AT/FP DESIGN GUIDELINES UFC 4-010-01 DoD Minimum Antiterrorism Standards for Buildings (9 Feb, 2012 w/ Change 1, 1 Oct 2013) UFC 4-022-02 Selection and Application of Vehicle Barriers (8 June 2009, w/ Change 1, 9 Aug 2010) UFC 4-023-03 Design of Buildings to Resist Progressive Collapse (14 July 2009, w/ Change 1, 27 Jan 2010) Provides design requirements necessary to reduce the potential of progressive collapse for new and existing facilities that experience localized structural damage through normally unforeseeable events.
AT/FP DESIGN GUIDELINES PBS-P100 US General Services Administration (GSA) Facilities Stds for the Public Buildings Service (primarily Chapter 8) GSA Site Security Design Criteria (predecessor to ISC) Establishes principles and lays out the process to follow in designing site security for any Federal project ISC Security Design Criteria for New Federal Office Buildings and Major Modernization Projects, Medium-High-Level Construction ISC Security Design Criteria, Part I ISC Security Design Criteria, Part II ISC Security Standards for Leased Spaces Note: The Whole Building Design Guide (WBDG.org) has a good article comparing and contrasting ISC with UFC approach.
ISC SECURITY DESIGN CRITERIA
WHAT PROJECTS NEED TO MEET THESE REQUIREMENTS? DoD Buildings New Buildings Must meet Existing Buildings Triggers MAJOR INVESTMENTS - GREATER THAN 50% VALUE CHANGE IN OCCUPANCY LEVEL WINDOW REPLACEMENT Other buildings deemed important by owner/occupants ANTI- TERRORISM / FORCE PROTECTION JANUARY 8, 2015
AT/FP DESIGN STRATEGIES Maximize Standoff Distance Prevent Building Collapse Minimize Hazardous Flying Debris Provide Effective Building Layout Limit Airborne Contamination Provide Mass Notification
AT/FP DESIGN STRATEGIES CASE STUDY OKLAHOMA CITY BOMBING (1995) 168 deaths, 680 injuries Maximize Standoff Distance Truck Bomb 5,000 lb TNT equivalent Truck was located in building drop off zone Prevent Building Collapse The bomb compression wave caused floors 4 and 5 to shear up and off their columns and collapse on to floor 3. Floor 3 included a large transfer beam. All the vertical columns on the southern perimeter that were connected to the transfer beam collapsed, along with any floor sections that depended on those columns for vertical support Building collapse contributed to a majority of deaths Minimize Hazardous Flying Debris Broken glass accounted for 5% of deaths and 69% of injuries
AT/FP DESIGN STRATEGIES CASE STUDY
AT/FP DESIGN PROCESS Determine building occupancy Determine applicable level of protection Determine standoff distance Determine applicable explosive weight Type I (no controlled perimeter) Type II (within controlled perimeter) Determine building construction types If conventional construction distances are met, detail building per UFC standards If conventional construction distances are not met, design building systems for actual blast loads (dynamic - SBEDS or equivalent or static methodology)
OCCUPANCY CATEGORIES DoD Standards Applicability: Low occupancy: < 11 people and < 1 person per 430 sf Inhabited: 11 people and 1 person per 430 sf Primary gathering and billeting: 50 people and 1 person per 430 sf ISC Standards Applicability (partial): Level I: 100 people, and 10,000 sf Level II: 101 to 250 people and 10,001 to 100,000 sf Level III: 251 to 750 people and 100,001 to 250,000 sf Level IV: > 750 people and > 250,000 sf
AT/FP DESIGN ASSUMPTIONS - UFC 4-010-01 UFC 4-010-01 is not intended to address all potential AT/FP threats AT/FP design is intended to address baseline threats and provide general protection Threats are assumed to be directed against DoD personnel Protection against worst case scenario for each building would be cost prohibitive Requirements differ for new and existing buildings
AT/FP DESIGN ASSUMPTIONS EW I Controlled perimeters channel vehicles to access control points or force aggressors to breach the barrier overtly Vehicle bombs of the size of EW I are likely to be detected during a search, and are assumed to not penetrate a controlled perimeter. It is assumed that vehicle bombs (EW I) will be parked covertly without being noticed (in legal parking areas) Vehicle barriers for roads and parking areas (outside of access control points) are not req d to stop moving vehicles. Penetration of these barriers is assumed to be observed.
AT/FP DESIGN ASSUMPTIONS EW II Bombs of the size of EW II is assumed to enter a controlled perimeter undetected. Aggressors will not attempt to place explosive devices in areas near buildings where devices could be visually detected (hidden in trash containers, beneath parked vehicles, etc). Hand delivered bombs will be at least 6 in height Roadways and parking do not require physical barriers. Ensure that driving outside boundaries would draw attention.
STANDARD 1 STANDOFF DISTANCE Increasing standoff distance is easiest method to minimize blast loading. Standoff distance is measured to roadways, parking areas and driving lanes within parking areas (new bldgs) Blast pressure varies linearly with charge weight. Doubling charge weight = 2x blast pressure. Blast pressure is inversely proportional to cube of standoff distance. Doubling distance = 8x reduction in blast pressure. 1 lb explosive at 10 ft standoff = 125 lb explosive at 50 ft standoff
STANDARD 1 STANDOFF DISTANCE
STANDOFF DISTANCE / CLEAR SPACE Eliminate hiding places for explosives (6 height) Items to plan for: Vehicle parking Mechanical equipment locations Dumpsters Service access and fire lanes (control) Landscaping Vehicle drop off (OK for certain uses)
STANDARD 1 STANDOFF DISTANCE For the structure, if the standoff distances are achieved, conventional construction may be used. If the maximum standoff is not achievable, the minimum can be used with a hardened structure. Controlled (gated) parking may be provided within CCSD for buildings where vehicle access is req d (i.e. vehicle maintenance buildings)
STANDARD 1 STANDOFF DISTANCE Revised for 2012 Distances apply to both new and existing. (Some exceptions.) Controlled perimeter or not. Type of use. Load bearing element or not.
STANDARD 1 STANDOFF DISTANCE New Table for 2012 Identifies basic types of construction. Using letters from Table B-1, find Standoff Distance. Note: There is significant interplay between determining standoff, and costs of windows & doors.
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STRUCTURAL SYSTEM TRADE-OFFS System mass helps blast resistance. Light gage stud systems have poor performance: Conventional construction assumes slip track connection at top of walls System performance can be enhanced with individual connection clips (The Steel Network or equivalent) Systems with partial height cladding (i.e. masonry wainscot) use the more conservative values for CCSD
IMPORTANT STAND-OFF DISTANCES Distance to controlled perimeter less than 200 ft Both Explosive Type I and II are considered Distance to controlled perimeter exceeds 200 ft Explosive Type II will govern No need to consider Explosive Type I
IMPORTANT STAND-OFF DISTANCES CCSD apply to wall assemblies. Windows and doors still need to be designed for actual blast pressures. Steel stud wall at 165 stand-off = minimal impact to window design Concrete wall at 16 stand-off = significant impact to window design Window and Door Construction will be heavier and more expensive at stand-off distances less than: 82 ft for Explosive Type I 33 ft for Explosive Type II Dynamic Analysis of Windows and Doors ($$$) is required for standoff distances less than: 43 ft for Explosive Type I 23 ft for Explosive Type II
STANDARD 2 CLEAR SPACE Required to be equal to the conventional construction standoff for Explosive Weight II, instead of 10 meters. No parking within unobstructed space (including handicapped parking or gov t vehicles) No plantings or site features that would allow for concealment of explosive devices 6 inches or greater (brief case sized object). For trees, no foliage extends lower than 3 feet above the grounds. Equipment can be within this clear zone if in a cage. Trash enclosure may be within this clear zone if designed to mitigate the blast loading.
CONTROLLED PARKING Vehicles may be parked within stand-off distances Access to vehicles is continuously controlled Vehicles are never removed from restricted access area Controlled parking is limited to authorized vehicles, enforced thru physical security measures (card operated gates, vehicle checks, etc) Mitigate the introduction of hand delivered explosives into controlled parking areas (control pedestrian access) by fencing Fencing and walls shall be a minimum of 6 ft high Types of vehicles normally located within controlled parking areas: Emergency vehicles Command and Operations support vehicles Mobile ground tactical platforms Vehicles within maintenance facilities
STANDARD 3 DRIVE UP/DROP OFF Image courtesy of BCRA Design The nature of some facilities requires Drive Up/Drop Off areas. In these cases: Prohibit parking. Clearly mark through paint and signage. Do not locate under inhabited portions of the building. Systems shall be in place to identify suspicious vehicles. Stand-off distance measured to legal parking spaces not drive aisle
STANDARD 4 ACCESS ROADS Access roads can be controlled simply and economically through the use of secured entry gates. Maintenance, or other access roads (including fire lanes) must have access control. Local site security must ensure limited access is maintained.
STANDARD 5 INTEGRAL PARKING Avoid parking beneath or on the rooftop of an inhabited building. If such parking is unavoidable, access control can be implemented, as well as designing the structure for blast effects.
STANDARD 6 PROGRESSIVE COLLAPSE AVOIDANCE Ronan Point Apartment, Newham, East London May 16, 1968 Alfred P. Murrah Federal Bldg, Oklahoma City, OK April 19, 1995
STANDARD 6 PROGRESSIVE COLLAPSE AVOIDANCE Implement UFC 4-023-03 Design of Buildings to Resist Progressive Collapse. TWO APPROACHES TO PROGRESSIVE COLLAPSE Tie Force Method Alternative Path Method Will also require Enhanced Local Resistance in some instances
STANDARD 6 PROGRESSIVE COLLAPSE AVOIDANCE TIE FORCE METHOD Horizontal Ties Peripheral Ties Vertical Ties Vertical straps used on Third Division Drive Whole Barracks Renewal at Joint Base Lewis-McChord. APPLICABILITY Very Low Level requires satisfaction of Horizontal and Peripheral Ties. Low Level requires satisfaction of Horizontal and Peripheral Ties, plus Vertical Ties or Alternative Path.
STANDARD 6 PROGRESSIVE COLLAPSE AVOIDANCE ALTERNATIVE PATH METHOD Analytically remove different elements from the structural model and ensure that structure can bridge over this location. APPLICABILITY Medium and High Levels of Protection require satisfying all tie force requirements, plus the Alternative Path Method.
STANDARD 7 STRUCTURAL ISOLATION Design additions to buildings to be structurally independent. Alternatively, evaluate entire structure to ensure that Standard 6 is satisfied with the addition included. "Seismic Joint"
STD 8 BLDG OVERHANGS & BREEZEWAYS Avoid designs with overhangs and breezeways with inhabited spaces above them where people could gain access to the areas underneath the overhangs. No roadways or parking areas under overhangs. Ensure areas underneath overhangs are clear of obstructions. Overhangs may be considered extensions of unobstructed space. Provide protection for Explosive Weight II placed at the edge of unobstructed space.
STANDARD 9 EXTERIOR MASONRY WALLS Unreinforced masonry walls are prohibited for the exterior walls of buildings. Masonry veneer applied to wood or metal studs are allowed. Note that Table B-2 included a wall type labeled Unreinforced Masonry. This is included for the analysis of existing buildings only. Existing unreinforced walls that do not meet conventional construction standoff distances shall be mitigated.
STANDARD 10 WINDOWS & SKYLIGHTS Conventional construction standoff distances do not apply to windows and doors. Minimize hazards from flying debris from windows and skylights. Design for glazing resistance determined by ASTM E1300 to satisfy the 3-second duration load from ASTM F 2248 (Very Low and Low Level of Protection). Glazing to be constructed with special laminated glass with polyvinyl-butyral (PVB) interlayer. Window frames and mullions to be aluminum or steel.
STANDARD 10 WINDOWS & SKYLIGHTS Structural support requirements are relaxed over previous versions. $$$ - dynamic analysis req d for stand-off distances less the 43 ft (Explosive Type I) or 23 ft (Explosive Type II). Skylight glazing will be designed as a minimum to break, but remain in the frame. Translucent, insulated wall panels (Kalwall) is an alternate glazing material.
STANDARD 10 WINDOWS & SKYLIGHTS Exterior Stairwells and Covered or Enclosed Walkways If exterior, these areas on not considered routinely occupied. Glazing is not req d to comply with provisions of Standard 10 Components behind these areas must be designed for blast load and windborne debris resistance. Design building components behind these areas as if stairwells and walkways were not present. Window Repair in Buildings 3655, 3656 and 3657 at Fort Lewis to meet UFC-4-010-01 AT/FP standards.
STANDARD 11 BUILDING ENTRANCE Entrance should not face or provide sightlines to installation perimeter or uncontrolled vantage point. If it is impossible to locate entrances away from uncontrolled areas, provide screening to block lines of sight.
STANDARD 12 EXTERIOR DOORS Doors should swing outward. Glazed doors, must meet glazing, but not frame requirements. Transoms and sidelights shall meet window req s Doors must be designed for blast, or positioned to avoid door being propelled into occupied space. Ensure overhead doors do not open into inhabited spaces, or design to avoid being propelled into occupied space. Vestibules are considered not routinely occupied. Inner doors and glazing shall be designed for blast load and windborne debris (see exterior stairwells and enclosed walkways).
ARCHITECTURAL DESIGN Standard 13 Mail Rooms and Loading Docks Location: Locate mailrooms and loading docks on building perimeter to facilitate future modifications. Proximity: Locate as far as possible from heavily populated areas of the building. Seal: Mailroom perimeter walls to be full height, and sealed to structure to maintain negative pressure. Standard 14 Roof Access Eliminate any exterior roof access points. Standard 15 Overhead Mounted Arch Features Minimize features in excess of 14 kg (31 lbs). Where included, design for horizontal anchorage of 0.5 times weight and vertical of 1.5 times weight.
ELECTRICAL AND MECHANICAL DESIGN Standard 16 Air Intakes Air intake to be located above 3 meters. Standard 17 Mail Room Ventilation Dedicated system with isolation controls. Maintain room at negative pressure. Standard 18 Emergency Air Distribution Shutoff Shutoff switch for outside air intake. Critical areas can use recirculated air. Standard 19 Equipment Bracing For overhead equipment weighing in excess of 14 kg (31 lbs), mount similar to overhead architectural features
ELECTRICAL AND MECHANICAL DESIGN Standard 20 Under Building Access Control access to under building spaces such as crawlspaces Standard 21 Mass Notification UFC 4-021-01 identifies the requirements for a Mass Notification system. Mass notification provides real-time information and instructions to people in a building, area, or site using intelligible voice communications along with visible signals, text, and graphics.
VEHICLE BARRIER SYSTEMS Typically required at vehicle access to establish controlled perimeter. UFC 4-022-02 provides information related to the selection of vehicle barrier systems and traffic calming options Vehicle barriers are divided into active and passive barrier systems. Vehicle barriers must be rated assemblies, which have been subjected to full scale testing. Installed barriers must comply with all construction details of the tested assembly.
PASSIVE BARRIER ASSEMBLIES UFC 4-022-2 provides recommendations for several pretested passive vehicle barriers. These systems are typically non-proprietary tested systems.
ACTIVE BARRIER ASSEMBLIES
DESIGN CRITERIA Kinetic Energy Developed by Vehicle, ft-lbf x 1,000
PASSIVE BARRIER CAPACITIES
FULL SCALE TESTING
UWT BARRIER OPTION A
UWT BARRIER OPTION A
UWT BARRIER OPTION B
UWT BARRIER OPTION B
UWT BARRIER OPTION C
UWT BARRIER
QUESTIONS? To download a copy of this presentation, please visit the News section of AHBL s website at www.ahbl.com. Thank you to Cal Pipe Security Bollards for use of the bollards video.