Fabric Covered Buildings Specifications



To provide minimum specifications for fabric covered buildings promoting quality, value, longevity, and competition.

These specifications outline the design, materials, and fabrication of metal building frames designed to be covered with a non-structural weather tight fabric membrane. These specifications are an outline of performance to ensure that the architect, engineer, building and/or building owner understand the basis for design, manufacture, and application of all manufacturer’s fabric covered building systems.

It is the requirement of the architect, engineer, building and/or building owner to understand and specify the design requirements necessary for the project. Because of the continuing program of research, development, and building code progression, specifications are subject to change without notice.

Detailed Building Specifications

_________________________________ Building Location
_________________________________ Building Usage
_________________________________ Building Frame Type
_________________________________ Building Design Code References
_________________________________ Cover: Type and Color
_________________________________ Building Width
_________________________________ Building Height
_________________________________ Building Length
_________________________________ Building Eave Height
_________________________________ Building Eave Clearance
_________________________________ Building Eave Width
_________________________________ Building Clearspan
_________________________________ Building End Wall #1, see attached DWG1
_________________________________ Building End Wall #2, see attached DWG2

Building Frame Description

Arched Top – Semi circular shaped open web truss design with various round or square high strength structural tubing  (building may not have interior columns).

Centered Gable – is a continuous rigid frame building with the ridge peak in the center of the building, consisting of tapered or straight columns and tapered rafters (the building may or may not have interior columns).

Offset Gable – is a continuous rigid frame building with the ridge peak not in the center of the building, consisting of identical roof slopes or different roof slopes, consisting of tapered or straight columns and taped rafters (the building may or may not have interior columns).

Mono Slope – is a single slope gable ridge frame building that does not contain a ridge peak, consisting of tapered or straight columns and tapered rafters (the building may or may not have interior columns).

Building Frame Description

  • Building “Width” is measured from outside to outside of base plates
  • Building “Height” is measured from the bottom of the base plate to bottom outside of truss or beam
  • Building “Length” is measured from the center of the first rafter to the center of the last rafter
  • Building “Eave Height” is measured from the bottom of the base plate on the column to the intersection of the inside for the roof and the sidewall column
  • Building “Eave Clearance” is measured from the final above grade and outside underside of the building eave extension
  • Building “Eave Width” is measured from the outside of the building column to the outside of the building eave extension
  • Building “Clearspan” is measured between the column supports at the truss or beam connection to the column (on arch-topped or circular truss building clear span is measured between truss base plates).
  • Standard “Bay Spacing” shall be 4’, 5’, 6’, 8’, 10’, 12’, 14’, 15’, 16’, or 20’ between frame centerlines including the end bay references
  • ASCE 7-05, ASCE 7-10 – American Society of Civil Engineers, Minimum Design Load for Building and Other Structures
  • IBC 2006, IBC 2009, IBC 2012 – Engineered for Current Site-Specific Building Code
  • AWS 1.1, AWS 1.3 – American Welding Society Structural Welding Code
  • NFPA 701 – National Fire Protection Association Fire Test for Flame Propagation of Textile and Films
  • AISC 360-05 – Specification for Structural Steel Buildings
  • AISI 2007 – North American Specifications for Design of Cold-Formed Structural Members
  • ANSI / AISC 341-05, 341-10 – Seismic Loading, Including Slip Critical Joints
  • ASTM A500, ASTM A513 – Hot or cold-form electric-resistance welded and seamless carbon steel structural tubing in round, rectangular, and square shapes
  • ASTM D529, ASTM 572 or ASTM A36 – Steel for tampered built-up beams section with minimum yield of 42,000 / 50,000 / 55,000 psi as indicated by the design requirements
  • ASTM A123 – Zinc coating (galvanizing) by the hot-dip process on iron and steel after manufacturing processes. This specification does not apply to wire, pipe, tube, or steel sheet which is pre-galvanized before manufacturing (galvanized on specialized or continuous lines).
  • ASTM A307, ASTM A325, ASTM A563, ASTM F436 – Type 1, heavy hex steel structural bolts; heavy hex carbon-steel nuts; hardened carbon-steel washers
  • ASTM A153 – Hot dip zinc coating on iron and steel hardware
  • Corrosion Resistance References – ASTM A193 B8- Standard specification for stainless steel bolts
  • ASTM A492-95 – Specification for stainless steel cable (wire rope)

Shop Drawings

  • Provide 11”x17” prints including a plan view, section views, connection details, base
    plate location and design, and structural analysis data signed by the engineer of record
    Governing Building Code
  • The building will comply with ASCE-7 Standard
  • Building Use Category
  • To be determined by an engineer of record, unless specified by contract
  • Design Loads
  • Shall be as specified and set forth in the contract, and shall be in accordance with Governing Building Code
  • May include Dead Load, Roof Live Loads, Wind Loads (Speed and Exposure), Roof Snow Load, Seismic Loads, Collateral Loads, Auxiliary Equipment Loads, and/or other applied or specified loads

Load Calculations and Reactions at Base Plate

Shall be applied simultaneously with concentrated loads, design building system to withstand the most critical of load factors according to the governing building code and the engineer of record.

Certifications – Can be provided per project requirements, design, or permitting IAS-AC472 Certification – Provide a signed statement from the tapered built-up beam supplier that the tapered built-up beams were produced in an IAS-AC472 certified facility by an IAS-AC472 certified manufacturer.

ASTM A123 Certification – Provide a signed statement from the source of zinc application that the coating meets the minimum of 2.2 oz/ft2 (+/- 5%), of continuous zinc coating on interior and exterior surfaces, also certify that the zinc used in the process is 99.9% lead free, unless specified by contract documents 1 oz. of zinc/ft² (320g/m²) of surface = to 1.7 mil (43um).

Fabric Certification – Provide a signed statement from the fabric manufacturer that fabric material supplied meets the specifications and the fabric material is of standard quality and free from defects. Provide original product data sheets from approved fabric suppliers. Include 8.5”x11” samples for color selection and upon request provide seam testing procedures per ASTM D4851: sheer test and creep test.

Welding Certification – Provide a signed statement from the building manufacture that all welding was performed by a certified welder, include a copy of the welder’s certificate with welding certification.

Special Inspections – Provide signed statement per IBC section 1704 Special Inspections when required by Governing Building Code Sealed Site-Specific Drawings by the Engineer of Record.

Sealed by a licensed professional engineer in the state of building use.


Standard material warranty on fabric covered building system. Warranty for fabric: 20-year pro-rated warranty. Warranty for hot-dipped galvanized manufactured components, including corrosion and structural integrity: 20 years. End user must comply with maintenance schedule. See warranty for specific details and limitations.


As supplied from manufacturer to provide recommended maintenance program intervals and detailed ownership guidelines; required by the end user for compliance for warranty coverage.

Quality Assurance

Single source responsibility: obtain fabric covered building system components including structural framing, industrial covering, and accessories from one source.

Manufactures Qualifications: provide a fabric covered building system manufactured by a firm indicated or other owner approved building system supplier, which is experienced in manufacturing fabric covered building systems, meet all of the required specifications, has been in continuous operation for ten (10) years with the same corporate identity, with a successful record in service and performance in the fabric-covered building industry.

Pre-Approved Manufactures,
Accu‐Steel Inc
PO Box 201
Templeton, IA 51463

Non-Approved Suppliers, other fabric-covered building system manufacturers claiming equivalent performance characteristics but have deviations from indicated specifications may be considered, provided the deviations do not change the design or performance of the building system, burden of proof for performance equivalent is solely on the nonapproved supplier.

Requests for approval must be made in writing prior to any bid submittal and must contain detailed information on deviations performance from indicated specifications for consideration. The owner will determine equivalent performance requests from non-approved suppliers.

Fabric covered building system with deviations from the specification will not be accepted unless the owner issues a written approval for all deviations prior to bid submittal.



The building manufacturer shall use standards, specifications, recommendations, findings and/or interpretations of professionally recognized groups such as ASCE, AIS, AISC, AISI, AWS, ASTM, MBMA, Federal Specifications, and unpublished research by MBMA as basis for establishing design, drafting, fabrication, and quality criteria, practices, and tolerances.

In all instances, however, the manufacturer’s design, drafting, fabrication and quality criteria, practices, and tolerances shall govern, unless specified by contract documents. All manufactured metal components shall be designed for a hot-dipped galvanized coating to ASTM A-123.

Shop fabricated framing components to indicated size and section with base plates, bearing plates, stiffeners, and other items required for erection welded into place. Cut, form, punch, drill, and weld framing for high strength bolt assembly.

Primary Framing Members

Manufacturer’s standard structural primary framing system designed to withstand required loads and specified requirements; primary framing includes transverse and lean-to frames; rafter and canopy beams; a sidewall; intermediate; end wall and corner columns, and wind bracing.

Open Web Truss – Manufactured from High Strength Structural Tubing, ASTM A500 / A513; minimum allowable tubing thickness 14 gauge or .083 inch; minimum 50 KSI yield, 55 KSI tensile; truss cords are to be cold formed and shop welded. Sheared, flattened, or deformed tubing is not allowed in the truss design. Diagonal center material supporting rafter truss cords shall not be gapped greater than 1 inch. Diagonal center material that requires venting for hot-dip galvanizing shall be in a uniform manner to promote strength and coating quality. Irregular venting by torching or grinding will not be allowed for hot-dip galvanizing.

Built-up Beams – Manufacturer’s standard structural primary rigid clear-span I-shaped frame section from specified ASTM D529, ASTM 572 or ASTM A36 – Steel for tapered built-up beams section with minimum yield of 42,000 / 50,000 / 55,000 psi as indicated by the design requirements; join flanges to webs of built-up members by a continuous submerged arc welding process; weld or bolt clips to frames for attaching secondary framing members.

Secondary Members

Manufacturer’s standard secondary framing members include purlins, girts, eave struts, flange bracing, base members, gable angles, clips, headers, jambs, and other miscellaneous structural members. Fabricate framing from cold-formed or structural steel, hot-dip galvanized coating to meet ASTM A123 unless specified by contract documents.


Shall be designed so not to interfere with clear span interior space, engineered from cable or rod and be made from a material or have a coating that is consistent with the buildings performance standards. Brace compression flange of primary framing with steel angles or cold-formed structural tubing between frame web and purlin to girt web, so flange compression strength is within allowable limits for any combination of loading.

Cable – Minimum ASTM A475, 5/16” diameter, extra high strength grade, class B zinc-coated, 7 strand steel, with threaded end anchors.

Rods – ASTM A36/ A36M; ASTM A572/ A572M, grade 50 or ASTM 529A/A529M grade 50; minimum 1/2 inch diameter zinc coated ( hot dip galvanized) steel; minimum of 6” threaded on each end.

End Wall Framing Members

Manufacturer’s standard primary end wall framing fabricated for field-bolted assembly to comply with required loads and specified requirements; end wall and corner columns from high strength steel (HSS) section from structural steel shapes; shop welded, built-up steel shapes, cold-formed structural steel; with manufacturer’s standard thickness.

Fabric Membrane

Shall be designed so no life safety issues are created in the event of a fabric loss, the building structure shall not rely on the fabric membrane for structural stability, and tension fabric membrane analysis is not allowed in building design. Shall be water and mildew resistant, insect-proof, UV (Ultra-Violet) stabilized, be durable to extreme climatic variations and corrosive environments, and have a flame spread properties that meet Class A per ASTM E84 method.

Pre-approved fabric membrane supplier
Engineered Coated Products (ECP), a division of Intertape Polymer Group (IPG) FRU-88X-6mil, Nova-Shield IITM and ArmorKote TM, 14.8 oz polyethylene fabric.

Fabrene, Engineered Shelter Fabric, 13 oz. polyethylene fabric with Enduro-Loc™ technology.

The manufacturer shall provide a Fire Retardant (FR) Fabric option on request; FR material shall meet the following flammability standards: NFPA 701 Large Scale, UBC Standard 31-1, California Fire Marshall CAC Title 19 par.1237.1, UFC 3-301-01 Standard Methods of Fire Tests for Propagation of Textiles and Film, 2004 Edition.

Fabric Cover Retention

Fabric membrane shall be attached to primary members only; any primary member that has fabric attached shall be braced.

Fabric cover building shall be designed to utilize an aluminum keder track on the primary member with an independent cover secured between aluminum keder tracks. Aluminum keder track shall be attached to primary members every 8 inches with weather-tight screw; an insert, PVC cap, or flap shall weatherproof the keder track.

Narrower arched topped or semi-circular shaped structures may utilize a strap and ratchet system with a single or multiple monolithic designed cover attached to primary members, optional keder track, any primary member that has fabric attached shall be braced.


High strength bolts for structural framing to meet ASTM 307 or ASTM A325, bolts, nuts, and washers shall be hot-dip galvanized to ASTM A153.

Fasteners and hardware accessories shall be of types and size best suited for purpose of building as recommended by the engineer of record.

Factory-Applied Finish

Provide a minimum of 3.9 mils hot-dip galvanized, ASTM A123, of zinc on all manufactured building components unless specified by contract documents.

Hot-dip galvanizing zinc or other specified by contract documents coating shall be applied after steel fabrication.

All manufactured steel component surfaces shall have a minimum of 2.2 oz/ft2 (+/- 5%), of continuous zinc coating on interior and exterior unless specified by contract documents. 1 oz. of zinc/ft² (320g/m²) of surface = to 1.7 mils (43um).

Structural bolts, nuts, and washers are to be Hot-Dip Galvanized to ASTM A153
Items supplied by building manufacturer but not fabricated by building manufacturer shall be made from a durable material or have a factory finish or coating appropriate for building use and application.

In-line, pre-galvanized, continuous flow zinc process steel
Does not meet ASTM A123 requirements, does not meet minimum continuous zinc surface coating requirements, and does not provide post-fabrication or weld (exterior or interior) corrosion protection.

Additional Components and Accessories

Provide accessories as standard with fabric building systems manufacturer and as specified. Fabricate and finish accessories at the factory to the greatest extent possible, by manufacturer’s standards procedures and process. Comply with indicated profiles and with dimensional and structural requirements, and be made from a material or have a coating that is consistent with the buildings performance standards.

  • Fabric Gather Doors – rectangular door pipe, HDG door track, no roller or bearings
  • Over Head Door Framing – designed for applicable wind loads, opening size by owner
  • Personal Doors – 3’‐0” x 7’‐0” poly core door, universal swing, aluminum frame standard
  • Eaves –availability varies by building design, variable width, and vent screen optional
  • Lovers – fixed or variable blade, aluminum, HDPE, fiberglass screening available
  • Insulation – availability varies by building design
  • Gutter and Downspout – availability varies by building design
  • Ice Guard – availability varies by building design
  • Corrosion Resistance Package – may include depending on the final design: stainless fasteners, cables, ratchets, additional ventilation, powered ventilation, additional corrosion barrier coating applied to hot-dip galvanizing zinc finish in critical areas.

Delivery, Storage, Handling

Delivery – Deliver material to the job site in manufacturer’s original, unopened containers and packaging with labels clearly identifying building items

Storage – Store materials in accordance with manufacturer instructions, clean dry and well-ventilated area, above ground on blocking, do not allow the material to become wet, stained, or dirty

Handling – Handle materials to protect materials, coatings, and finishing during transportation and installation to prevent damage or staining, handle fabric in accordance with the manufacturer’s instructions to avoid fabric material and coating damage.

Building Anchorage and Foundation

Building Anchorage – building anchors bolts shall be designed to resist the maximum column reactions resulting from the specified load combinations, have a coating appropriate for building use. The design and loading shall be specified by the manufacturer, anchor bolts will be sized and supplied by the contractor and NOT by the manufacturer, unless specified by contract documents.

Foundation – foundations shall be adequately designed by a qualified foundation engineer to support the building reactions and other loads which may be imposed by the building use. The design shall be based on the specific soil conditions of the building site. Foundation engineer shall be retained by OTHER than the manufacturer. The manufacturer assumes NO responsibility for the integrity of the foundation unless specified by contract documents.

Building Installation

Erector Qualifications: experienced erector who specialized in installing work similar in material, design, and extent to that is certified in writing by the fabric cover building system manufacturer as qualified for erection of manufacturer’s products, using proper tools and equipment, erector shall follow good sound and safe procedures and guidelines and will work in accordance with any applicable federal, state, or local laws.

Weather Limitations: Proceed with installation only when weather conditions permit metal and fabric components to install according to manufacturer’s written instructions, warranty requirements, and in a safe and efficient manner.

If you have any questions or concerns, feel free to contact Accu-Steel for more information.

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