Unit Objectives Explainarchitectural considerations to mitigate impacts from blast effects and transmission of chemical, biological, and radiological agents from exterior and interior incidents. Identifykey elements of building structural and non- structural systems for mitigation of blast effects. Text Box: References FEMA Building Vulnerability Assessment Checklist, Chapter 1, page 1-46, FEMA 426 Building Design Guidance, Chapter 3, FEMA 426 FEMA 430, Primer for Incorporating Building Security Components in Architectural Design Unit Objectives (cont.) Compareand contrast the benefit of building envelope, mechanical system, electrical system, fire protection system, and communication system mitigation measures, including synergies and conflicts. Applythese concepts to an existing building or building conceptual design and identify mitigation measures needed to reduce vulnerabilities. Layers of DefenseFEMA 452, Figure 2-2: Layers of Defense, p. 2-3 Third Layer of Defense FEMA 426, Figure 2-8: Concept of stand-off distance, p. 2-22 (left) FEMA 426, Figure 4-5: Explosive blast range to effects, p. 4-11 (right) Text Box: Stand-off Distance – primary impact on design and construction of building envelope and structure against design basis threat (explosives)To protect against unauthorized vehicles approaching target buildings Third Layer of Defense•Red –Very severe damage, possible collapse•Yellow –Very unrepairable structural damage•Green –Moderate repairable structural damageDetonation at 80 feetDetonation at171 feetDetonation at 400 feetStand-offversusGivenHardeningFEMA 426, Figure 4-9: Stand-off distance versus blast impact–Khobar Towers, p. 4-15 Third Layer of Defense Text Box: Less stand-off requires More mass More steel Thicker and stronger glass Better door and window frame connection to building/wall Text Box: Third Layer of Defense Third Layer of Defense When hardening a building, the following should be considered: ..Progressive collapse ..Appropriate security systems ..Hardening the building envelope ..Appropriate HVAC systems to mitigate CBR ..Hardening the remaining structure ..Hardening and location of utilities Architecture –Building Configuration Low, Large Footprint Tall, Small Footprint Architecture –Building Configuration Rectangular versus “U”, “L”or “E” Avoid re-entrant corners Flush face versus eaves and overhangs FEMA 426, Figure 3-2: Re-entrant corners in a floor plan, p. 3-6 FEMA 427, Figure 6-3: Effects of building shape vs. air blast, p. 6-9 Shapes That Accentuate Blast Architecture –Building ConfigurationHardening –Story height vsStand-off ..Hardening of first three floors is critical as these take brunt of blast ..At third through sixth floor, hardening can be reduced due to reflection angle ..Above the sixth floor, conventional construction may be sufficient depending upon design threat and reflections off adjacent buildings 1765432 Architecture –Building Configuration Ground floor elevation 4 feet above grade Orient glazing perpendicular to principal threat direction Avoid exposed structural elements Pitched roofs and pitched window sills FEMA 426, Figure 3-1: Glazed areas perpendicularly oriented away from streets, p. 3-5 Architecture –Building Configuration Loading Docks ..Avoid trucks parking in or underneath buildings ..Design to prevent progressive collapse ..Ensure separation from critical systems, functions, and utility service entrances ..Separate loading docks from building critical functions ..Provide sufficient area for screening vehicles and packages ..Keep dumpsters away from buildings Architecture –Building Configuration Parking Considerations ..Restrict parking underneath buildings ..Well-lit, security presence, emergency communications, and/or CCTV ..Apply progressive collapse hardening to columns when parking garage is in building ..Garage elevators service garage only to unsecured zone of lobby FEMA 426, Figure 1-10: Non-redundant critical functions collocated near loading dock, p. 1-41 Architecture –Space DesignThe loading dock and warehouse provide single point of entry to the interior. The mailroom is located within the interior and not on exterior wall or separate HVAC system. The telecom switch and computer data center are adjacent to the warehouse. The trash dumpster and emergency generator are located adjacent to the loading dock. Architecture –Space Design Place unsecured or high risk areas outside building footprint Do not mix high risk and low risk tenants in same buildingLocate critical assets into interior of building Separate areas of high visitor activity (unsecured) from critical assetsFEMA 427, Figure 6-4: Improving layout of adjacent unsecured and secured areas, p. 6-10 Architecture –Space Design Eliminate hiding places Interior barriers Offset doorways Minimize glazing, particularly interior glazing near high-risk areas Lobby with security procedures configured to contain incidents (blast, CBR, armed attack) FEMA 426, Figure 3-3: Offset doors through foyer, p. 3-7 Building Exterior Architecture –Other Location Concerns •Safe havens / shelters •Office locations •Public toilets and service areas •Retail spaces •Stairwells •Mailroom Structural Systems GSA Progressive Collapse Analysis and Design Guidance for New Federal Office Buildings and Major Modernization Projects DoD Unified Facilities Criteria -Minimum Antiterrorism Standards for Buildings Text Box: Progressive Collapse Design Loss of columnLoss of interior column only if uncontrolled access occurs below. (Hardening may be an acceptable alternative) Loss of columnLoss of columnBUILDING PLANStructural SystemsProgressive Collapse ConceptBay Size Structural Systems --Collapse GSA and DoD criteria do not provide specific guidance for an engineering structural response model These organizations are working toward Interagency Security Committee consolidated guidance Owner and design team should decide how much progressive collapse analysis and mitigation to incorporate into design. Structural Systems --Loads and Stresses Murrah Federal Building, Oklahoma CityMurrah Federal Building, Oklahoma CityKhobar Towers, DhahranKhobar Towers, Dhahran Text Box: Ronan Point, London Structural Systems –Best Practices Consider incorporating active or passive internal damping into structural system (sway reduction in high-rise) Use symmetric reinforcement, recognizing components might act in directions opposite to original or standard design –flooring especially Column spacing should be minimized (<=30 feet) Structural Systems –Best Practices (cont.) Stagger lap splices and other discontinuities and ensure full development of reinforcement capacity or replace with more flexible connections –floors to columns especially Protect primary load carrying members with architectural features that provide 6 inches minimum of stand-off Use ductile detailing requirements for seismic design when possible Building Envelope During actual blast or CBR event, building envelope provides some level of protection for people inside: ..Walls ..Windows ..Doors ..Roofs Soil can be highly effective in reducing damage during an explosive event Minimize “ornamentation”that may become flying debris in an explosion. Building Envelope –Walls Design should ensure a flexible failure mode Resist actual pressures and impulses acting on exterior wall surfaces from design basis threats Withstand dynamic reactions from windows and windows stay connected to walls Use multiple barrier materials and construction techniques – composites can add ductility and strength at savings As desired Level of Protection increases, additional mass and reinforcement may be required Building Envelope –Best Wall Practices Use symmetric reinforcement, recognizing that components might act in directions opposite to original or standard design ..Lobbies and mailrooms Use wire mesh in plaster –reduces spalling/ fragmentation Floor to floor heights should be minimized (<=16 feet) Connect façade from floor slab to floor slab to avoid attachments to columns (one-way wall elements) ..Limits forces transferred to vertical structural elements No unreinforced CMU –use fully grouted and reinforced construction Text Box: Building Envelope – Best Wall Practices Building Envelope –Windows Balanced Window Design Glass strength Glass connection to window frame (bite) Frame strength Frame anchoring to building Frame and building interaction “Balanced Design” Building Envelope –Windows Glass (weakest to strongest) ..Annealed (shards) ..Heat Strengthened (shards) ..Fully Thermally Tempered (pellets) ..Laminated (large pieces) ..Polycarbonate (bullet-resistant) Building Envelope –Windows GSA Glazing Performance Conditions FEMA 426, Figure 3-4: Side view of a test structure illustrating performance conditions of Table 3-2, p. 3-22 Glazing Tape Sealant Building Envelope -Window Frames Goal: transfer load from glass to frame and retain glass in frameBite: ½inch minimumStructural sealant: ¼inch bead or wet glazeBiteWet Glaze (silicon) GlassFrame“Balanced Design” “Balanced Design” Building Envelope -Window Frames Goal: transfer load to building structureBalanced strength: glass, frame, and connection of frame to wall Building Envelope -Fragment Retention Film Clear tough polyester film attached to inside of glass surface with strong pressure-sensitive adhesive Also known as shatter-resistant film, safety film, or protective film Relatively low installation costs Level of protection varies with thickness of film and method of installation Limited life for FRF “Daylight Application” Building Envelope -Fragment Retention Film“Wet Glazing”(edge to edge) Building Envelope -Blast CurtainsInvented by British during WW IIKevlar curtainsAllow venting of blast wave while “catching” fragmentsMay be augmented with FRF Building Envelope -Catch Bar Plan ViewMust be centered on window and window panesFRF must be thick enough to hold the fragments (=7 mil) Laminated glass should have60 mil interlayerFEMA 427, Figure 6-7: Safe laminated glass systems and failure modes, p. 6-29 Building Envelope –Best Window Practices No windows adjacent to doorsMinimize number and size of windows -watch building code requirementsLaminated glass for high-occupancy buildingsStationary, non-operating windows, but operable window may be needed by building codeSteel versus aluminum window framing Building Envelope –Doors Balanced strength ..Door ..Frame ..Anchorage to building Hollow steel doors or steel-clad doors Steel door frames Blast-resistant doors available ..Generally heavy ..Generally expensive Building Envelope –Roofs FEMA 426, Figure 3-7: Sacrificial roof, p. 3-33 Text Box: Sloped sacrificial roof over protected roof/ceiling Sandbags or dirt layer Restrict access to roof Utility Systems Building Service ..Electric –commercial and backup ..Domestic water ..Fire protection water ..Fuel –coal, oil, natural gas, or other ..Steam heat with or without condensate return ..Hot water heat Utility Systems Building Service (cont) ..Sewer –piping and sewage lift stations ..Storm drainage ..Information ..Communications ..Fire alarm ..Security systems and alarms Utility Systems Entrances ..Proximity to each other ..Aboveground or underground ..Accessible or secure Delivery capacity ..Separate ..Aggregate Storage capacity ..Outage duration ..Planned or historical Mechanical & Electrical Systems Functional layout –physical separation or hardening Structural layout –systems installation Do not mount utility equipment or fixtures on exterior walls or mailrooms Avoid hanging utility equipment and fixtures from roof slab or ceiling Mechanical & Electrical Systems Overhead components, architectural features, and other fixtures > 14 kilograms (31 pounds), especially in occupied spaces ..Mount to resist forces 0.5 x W in any direction and 1.5 x W in downward direction (DoD Unified Facilities Criteria) ..Plus any seismic requirements Mechanical & Electrical Systems Distribution within building ..Looped or multiple radial versus single radial ..Pipe chases –horizontal and vertical –cross impacts Normal and emergency equipment locations ..Generators versus commercial switchboard or transfer switch ..Electric fire pumps versus diesel fire pumps Mechanical & Electrical Systems Restrict access -locks / alarms / surveillance ..Utility floors / levels ..Rooms ..Closets ..Roofs ..Security locks/interlocks comply with building code ..Building information ..Also consider for other systems Mechanical & Electrical Systems Building lighting and CCTV compatibility ..Intensity ..Resolution ..Angle ..Color Exit lighting –consider floor level, like airplanes Emergency lighting –battery packs have their place Mechanical & Electrical Systems ..Building specific ..System shutdown –configuration and access ..HVAC fans and dampers ..Include 24/7 exhausts, i.e. restrooms ..Zone pressurization ..Doors and elevator use ..Shelter-in-place Ventilation and Filtration –HVAC Control Options Mechanical & Electrical Systems ..Specialized exhaust for some areas –i.e., lobbies and mailrooms ..Air purge (e.g., 100 percent outside air if internal release) ..CBR filters to trap and prevent spread elsewhere ..Pressurized egress routes (may already exist) ..Filtered air supply or shutdown if release external Ventilation and Filtration –HVAC Control Options Plumbing and Gas Systems Same considerations as electrical and mechanical systems Added concern is fuel distribution ..Heating sources / open flames / fuel load Interaction with other systems during an incident ..Fuel versus alarms / electric / fire protection water / structure ..Water versus electronic / electric Fire Alarm Systems Considerations similar to information and communications systems, but tighter building codes ..Centralized or localized ..Fire alarm panel access for responding fire fighters or fire control center ..Interaction with other building systems ..Telephone / IT ..Energy management ..HVAC controls ..Off-premises reporting and when Communications -Information Technology SystemsLooped versus radial distributionRedundancy ..Landline, security, fire watch ..Copper ..Fiber optics ..Cell phones (voice, walkie- talkie, text) ..Handheld radios / repeaters ..Radio telemetry / microwave links ..SatelliteMass notification ..Loud speakers ..Telephone hands-off speaker ..Computer pop-up ..Pager Communications -Information Technology Systems (cont.) Empty conduits ..Future growth ..Speed repair Battery and backup power for IT ..Hubs, switches, servers, switchboards, MW links, etc. ..VOIP, building ops, alarms, etc. Fire stopping in conduits between floors Text Box: Secure dedicated lines between critical security functions Backup control center with same capability as primary Equipment Operations and Maintenance Preventive Maintenance and Procedures ..Drawings indicating locations and capacities are current? ..Maintenance critical to keep systems operational ..Critical systems air balanced and pressurization monitored regularly? ..Periodic recommissioning of major systems? ..Regularly test strategic equipment ..Sensors, backup equipment and lighting, alarms, and procedures tested regularly to ensure operation when needed? ..Backup systems periodically tested under worst case loadings? Equipment Operations and Maintenance Maintenance Staff Training ..System upgrades will require new training ..Specific instructions for CBR event (internal vsexternal release) ..Systems accessible for adjustment, maintenance, and testing Security Systems Purpose is to improve the reliability and effectiveness of life safety systems, security systems, and building functions. ..Detection ..Access control ..Duress alarms ..Primary and backup control centers –same procedures Electronic Security Systems Security Systems Channel visitors entering building to access control in lobby Signs should assist in controlling authorized entry Have sufficient lobby space for security measures (current or future) Avoid extensive queuing, especially outside building Proper lighting, especially if manned 24 hours/ day Hardened against attack based upon security needs Entry Control Stations Security Systems All buildings should have current plans ..Building evacuation with signage & emergency lighting ..Accountability –rally points, call-in ..Incorporate CBR scenarios into plans ..General occupant actions ..Response staff actions –HVAC and control centers Exercise the plans to ensure they work ..Coordinate with local emergency response personnel ..Test all aspects Emergency Plans Practical Applications What can be done with a reasonable level of effort? End of Chapter 3, FEMA 426 listing of mitigation measures ..Less protection, less cost, with less effort ..Greater protection, greater cost, at greater effort Building Materials: General Guidance All building materials and types acceptable under building codes are allowed. Special consideration should be given to materials having inherent flexibility and ability to respond to load reversals. Careful detailing is required for materials (such as pre-stressed concrete, pre-cast concrete, and masonry) to adequately respond to design loads. Construction type selected must meet all performance criteria of specified protection level. Desired Building Protection Level Component design based on: Design Basis Threat Threat Independent approach Level of Protection sought Leverage natural hazards design/retrofit Incorporate security design as part of normal capital or O&M program Use existing tools/techniques, but augment with new standards/guidelines/codes Summary Building Design Guidance and Mitigation Options Using the FEMA 426 Checklist will help identify vulnerabilities and provide recommended mitigation options. There are many methods to mitigate each vulnerability. Relatively low cost mitigations significantly reduce risk. Unit X Case Study Activity Building Design Guidance and Mitigation Measures Background Emphasis: ..Providing a balanced building envelope that is a defensive layeragainst the terrorist tactic of interest ..Avoiding situations where one incident affects more than one building system FEMA 426, Building Vulnerability Assessment Checklist Requirements Assign sections of the checklist to qualified group members Refer to Case Study, and answer worksheet questions Review results to identify vulnerabilities and possible mitigation measures