HEADER
TO: Honorable Chairperson and Members DATE: December 3, 1996
Board of County Commissioners

SUBJECT: Proposed Alternate
Ordinance amending the
FROM: Armando Vidal, P.E. South Florida Building
County Manager Code, Chapter 43

STAFF RECOMMENDATION
It is recommended that the attached alternate ordinance amending Chapter 43 (Fabric Awnings, Canopies and Tents) of the South Florida Building Code be considered for adoption.

MANAGER'S BACKGROUND
Staff concurs with the position of the Building Code and Product Review Committee that these fabric covered framework appurtenances present no greater threat or hazard than such ornamental improvements as decorative trim decorative wood shutters and stucco banding accents attached to the facade or exterior of a building. It is for that reason and following existing guidelines of other national standards and industry trends that staff recommends in its proposed alternate ordinance to exclude the need to require permits for construction and installation of these fabric covered framework appurtenances, except for cases where the installation of these frameworks project over and/or within public property, installed over areas providing the required public egress into and out of a private building, or installed over public assembly areas or common courtyards.

By limiting the permit requirement to these few exceptions, we can achieve a very streamlined approach to protecting the safety of the general public.

The alternate ordinance differs in three major areas from the original proposal prepared by the Building Code and Product Review Committee (BCPRC) as follows:

First, staff disagrees with the Committee's recommendation with respect to creating various types of classifications and wind load criteria that would condone the use of fabric covered framework structure designed for a 35 MPH wind velocity. In staff's opinion, these requirements place unrealistic restraints as to-having to secure these various types of structures during normal and everyday seasonal thunderstorm events. It also greatly reduces the current structural integrity in the SFBC, which requires a minimum design resistance capacity for a 75 MPH wind velocity.

The second major difference in the alternate ordinance proposed by staff is the inclusion of requirements to address the construction and installation of temporary and permanent membrane fabric cover structures using air-inflated or air-supported structural systems. Staff research of other national standards and model building codes shows that these documents consistently address all fabric or membrane covered structures under a single chapter, which helps maintain the continuity of the text.

Thirdly, staff considers the widely used narrative language throughout the Committee's proposal to be inappropriate for a technical document such as the SFBC, and in contradiction to the linguistic format of the remaining 49 chapters in the Code.

TITLE
ORDINANCE AMENDING THE SOUTH FLORIDA BUILDING CODE; AMENDING CHAPTER 43, RELATING TO FABRIC AWNINGS AND TEMPORARY AND MEMBRANE STRUCTURES; CREATING AN APPENDIX 'G' AS A COMMENTARY FROM THE BUILDING CODE AND PRODUCT REVIEW COMMITTEE ON CHAPTER 43; ADDING A NEW SECTION ON MEMBRANE STRUCTURES AND EXPANDING THE TENT SECTION TO INCLUDE OTHER TEMPORARY FABRIC STRUCTURES; PROVIDING SEVERABILITY, INCLUSION IN THE SOUTH FLORIDA BUILDING CODE, AND AN EFFECTIVE DATE.

BODY

BE IT ORDAINED BY THE BOARD OF COUNTY COMMISSIONERS OF DADE COUNTY, FLORIDA:

Section 1. Chapter 43 of the South Florida Building Code as amended, is hereby further amended to read as follows:1



CHAPTER 43
+FABRIC AWNINGS, >>FABRIC COVERED FRAMEWORK (FCF), CANOPIES, TEMPORARY STRUCTURES,<< AND [[TENTS]] >>MEMBRANE STRUCTURES

(For commentaries to this Section See Appendix "G"<<


4301 GENERAL
4302 DEFINITIONS
4303 PERMITS AND INSPECTIONS
4304 LOCATION AND USE >>FABRIC AWNINGS, CANOPIES AND FABRIC COVERED FRAMEWORK, (FCF)<<
4305 CONSTRUCTION >>FABRIC AWNINGS, CANOPIES AND FABRIC COVERED FRAMEWORK, (FCF)<<


4306 [[TENTS]] >>TEMPORARY STRUCTURES
4307 MEMBRANE STRUCTURES<<


-4301 _GENERAL

-4301.1 _GENERAL:_ Fabric awnings, canopies >>, fabric covered framework, temporary structures,<< and [[tents]] >>membrane structures<< shall be of materials, proportions and strength as set forth in this Chapter. Where more restrictive in respect to location, use size and height the limitations of zoning or other specific regulation shall apply.

4301.2 _PURPOSE:_ It is the intent and purpose of this part to regulate construction and location of >>fabric<< awnings, [[and]] canopies >>, fabric covered framework, temporary structures and membrane structures<< [[on private property]] and to set forth the conditions under which >>all<< [[awnings]] >>these structures<< may be constructed. [[over public property]]

>>4301.3 STANDARDS:

(a) Guidelines for Structural Condition Assessment of Existing Buildings ANSI/ASCE-11

(b) NFPA 101 Life Safety Code

(c) NFPA 102, Standard for Assembly Seating, Tents, and Membrane Structures

(d) NFPA 701 Standard Methods of Fire Test for Flame Resistant Textiles and Films<<



-4302 _DEFINITIONS

>>AIR-INFLATED STRUCTURE: A building where the shape of the structure is maintained by air pressurization of cells or tubes to form a barrel vault over the usable area. Occupants of such a structure do not occupy the pressurized area used to support the structures.

AIR SUPPORTED STRUCTURE: A building wherein the shape of the structure is attained by air pressure and occupants of the structure are within the elevated pressure area. Air-supported structures are of two basic types:


(a) SINGLE SKIN: Where there is only the single outer skin and the air pressure is directly against that skin.

(b) DOUBLE SKIN: Similar to a single skin, but with an attached liner which is separated from outer skin and provides an air space which serves for insulation, acoustic, aesthetic or similar purposes.<<

_AWNING: Any >>rigid or<< movable >>(retractable)<< roof-like structure, cantilevered, or otherwise entirely supported from a building. >>An awning is comprised of a lightweight rigid or removable skeleton structure over which an approved cover is attached.<< [[so constructed and erected as to permit its being readily and easily moved within a few minutes time to close an opening, or rolled or folded back to a position flat against the building or a cantilevered projection thereof, or is detachable.]]

CABANA: A sun and wind protection erected nearby and in connection with swimming areas having removable fabric roofs and walls, on a fixed metal frame.

>>CABLE-RESTRAINED AIR-SUPPORTED STRUCTURE: A cable-restrained air-supported structure is one in which the uplift is resisted by cables or webbing which are anchored to either foundations or deadmen. Reinforcing cable or webbing may be attached by various methods to the membrane or may be an integral part of the membrane. This is not a cable-supported structure.

CABLE STRUCTURE: A non-pressurized structure in which a main mast and cable system provide support and tension to the membrane and the membrane imparts structural stability to the structure.<<

CANOPY: Any fixed roof-like structure, not movable like an awning, and which is cantilevered in whole or in part self-supporting, but having no side walls or curtains other than valances not more than 18" deep. Lean-to canopies, fixed umbrellas and similar structures are included in this classification. Structures having side walls or valances more than 18" deep shall be classified as a tent or [[cabin ]] >>cabana<< as set forth herein.

FABRIC: Cloth or any material similarly flexible or woven, >>made of natural or synthetic material.

FABRIC COVERED FRAMEWORK, (FCF): A non-pressurized structure which is composed of a rigid framework to support tensioned membrane or fabric which provides the weather barrier.

FRAMEWORK: A skeletal or structural frame; an openwork frame structure

MEMBRANE: A thin, flexible, impervious material capable of being supported by an air pressure of 7.8 PSF, which corresponds to a 1.5 inch high column of water.

NON-COMBUSTIBLE MEMBRANE STRUCTURE: A membrane structure in which the membrane and all component parts of the structure are non-combustible as defined by section 401.

NON-REMOVABLE FABRIC OR MEMBRANE: Fabric or membrane material which is attached in such a manner as to prevent its removal except for complete replacement of the fabric or membrane.<<

ROLLER CURTAIN: Shall be included in the classification of a movable awning and shall be defined as having a roller attached to the lower or >>upper<< edge of a fabric and supported in whole or in part by the awning material.

SELF-SUPPORTING: Supported to the ground or construction below by columns or walls; but not cantilevered >>or attached to another structure<<.

TENT: A fabric-roofed structure, wholly or partially self-supporting, with side walls of any material.

-4303 _PERMITS, AND INSPECTIONS

-4303.1 _PERMITS:

_ (a) A permit shall >>only<< be required as set forth in Chapter 3 of this Code for the construction, [[fabrication,]] installation, repair or replacement of any >>fabric<< awning, canopy, >>fabric covered framework, (FCF)<< or any other >> non habitable<< fabric structure erected >>within,<< [[over]] >>or attached to any<< public or >>private<< property, [[used for business or industrial purposes, or over property when such structure is in whole or in part self-supported]] >>when extending over any portion of a court or yard beside a building serving as a passage from a required exit or exit discharge to a public street or installed over public gathering areas or common courtyards.<<.

EXCEPTION: >>(1) Building<< [[P]]>>p<>at the time it was permitted.

(b) A permit shall be required as set forth in Chapter 3 of this Code for the construction, fabrication, installation, repair or replacement of any temporary fabric structure and membrane structure, as defined in sections 4302, 4306 and 4307 of this code, erected within public or private property. Permit application and documents shall comply with section 4303.1(c) and 4306.4 of this code.

(c)<<[[(b)]] Application, for permit shall be accompanied by plans, and when required by the Building Official, such plans shall be prepared by a Florida registered professional Engineer or Architect, which Engineer or Architect shall be proficient in structural design. >>In lieu of compliance with the above requirement for sealed plans and calculations, a Notice of Acceptance from the Product Control Section may be provided, which Notice of Acceptance has not expired at the time of permit application. Plans approved under the Notice of Acceptance do not need to be resigned and resealed by an Architect or Engineer nor will duplicate calculations be required.

(d)<<[[ (c)]] Where the proposed structure is to be erected over public property, applications [[will only be accepted by licensed contractors]] >>and installations shall be performed by a licensed contractor registered to perform this type of work in Dade County. <<

[[(d) Application for the erection of a tent exceeding 100 sq. ft. in area shall be accompanied by written approval of all residents or owners of property located within a radius of 200'-0" of the erection site except that where a tent is to erected on private property for a period not to exceed 24 hours the permission of the adjacent property owners will not be required.]]

(e) Permits for the erection of a tent shall be revocable on 24 hours notice and shall be temporary and for a period not exceeding 30 days.


-4303.2 _INSPECTION:

_ (a) The permit holder shall request the Building Official to make a final inspection when the work is completed.

(b) The name of the manufacturer shall be affixed and shall be visible and legible.

>>(c) Fabric awnings, fabric covered framework, (FCF) and canopies shall have a permanent label affixed to each unit that states that the fabric membrane shall be completely removed and stored in a safe place during storm events with wind speeds equal to or greater than 75 mph.<<

-4304 _LOCATION AND USE

>>FABRIC AWNINGS, CANOPIES AND FABRIC COVERED FRAMEWORK, (FCF)<<

-4304.1 _LOCATION:

_ (a) (1) Fabric awnings>>, FCF<< and canopies located over public property or in areas accessible to the general public shall be constructed so that no rigid part of such fabric awnings>>, FCF<>7' - 0"<<.

(2) The minimum clearance under >>fabric<< awnings >>, FCF<< or canopies located over state highway right-of-way shall be as required by the Florida State Road Department.

(b) [[No cantilevered portion of an]] >>A fixed fabric<< awning >>, FCF<< [[and]] >>or<< canopy >>shall not extend<< over public property, >>more than two-thirds the distance from the property line to the nearest curb line in front of the building site,<< [[exceeding 9'-0" in projection shall extend]] >>as measured from the exterior face of the building<< nor shall any portion be closer than 18" to the curb line.

>>Exception: If installed over 14 feet in height, it may occupy the entire width of the sidewalk.<<

[[(c) Canopies in whole or in part supported to the ground, shall comply with the zoning set back for buildings except as may be otherwise regulated in Chapter 33 of this Code or in applicable zoning regulations.]]

[[(d)]]>>(c)<< [[Structures]] >>Fabric covered framework, (FCF)<<, in whole or in part of fabric, erected in connection with gasoline service stations may not be erected within 15'-0" >>of<< or where, flammable liquids are transferred.

[[(e)]]>>(d) Movable fabric awnings, FCF or canopies may extend over public property for a distance of not more than 5 feet, provided such awnings or any part thereof maintain a clear height of 8 feet above the sidewalk. All such movable awnings shall be supported on metal frames attached to the building.<<

[[(f)]] >>(e) Every fabric awning, FCF or canopy shall be located as not to interfere with the operation of any exterior standpipe, stairway, fire escape or any means of egress to and from the building.<<


-4304.2 _USE:

_ (a) (1) Fabric awnings >>, FCF<< and canopies may be used for the shading and weather protection of windows, door entrances, fruit and vegetable display, restaurant table not enclosed with insect screen and seats and playgrounds.

[[(2) Fabric awnings and canopies used for the shading or weather protection of cars or boats in connection with Group I Occupancies shall be limited to a size to cover not more than 2 such vehicles.]]

(b) Fabric awnings >>, FCF<< and canopies may not be used for general storage of combustible materials or goods packaged in combustible materials.

(c) Fabric awnings >>, FCF<< and canopies, may not be enclosed with any material other than a valance not more than 18" in vertical depth or fabric roller curtains for temporary shade and weather protection.

-4305 _CONSTRUCTION

>>FABRIC AWNINGS, CANOPIES AND FABRIC COVERED FRAMEWORK, (FCF)<<

-4305.1 _AREA:

_ (a) No fabric awning >>, FCF<< or canopy shall exceed the area of the building to which it is attached.

- [[(b) No fabric awning or canopy shall exceed 10% of the area of the lot on which such awning or canopy is located.]]

-4305.2 _MATERIAL:

_ (a) Fabric used for any purpose herein defined shall be >>flame resistant in accordance to NFPA 701 << [[a minimum of 10.10 army duck]]. Fabric for tents shall be flame-resistant.

(b) Supports for fabric awnings >>, FCF<< and canopies shall be of metal or similar durable material.

-4305.3 _DESIGN:

_ [[(a) (1) The minimum size of structural members of cantilevering awnings, or canopies or cabanas shall be not less than as set forth hereinafter, nor less than required to resist 75 mph wind with applicable shaped factors by rational analysis as defined in Sections 204 and 302 of this Code.]]

>>(a)<<[[(2)]] (1) Design of the [[structural frame]] >>framing members<<, shall not be based on removal or repositioning of parts, or the whole, during periods of 75 mph wind velocity.

[[(3)]]>>(2) Design of the structural framing members shall be based on rational analysis, using the applicable wind loads of Chapter 23 as shown below:

(3) The wind design loads for any fabric or membrane covered structure designed with a quick removal or breakaway membrane or fabric at wind velocities of 75 m.p.h., shall be based on the following criteria:
(aa) Minimum wind velocity of 75 m.p.h.
(bb) Importance factor based on Category IV, I = 1.0
(cc) Velocity pressure coefficient, Kz - Use Exposure "B" for all applications except that Exposure "D" shall be used for installations within the coastal construction zone as defined by Section 2302 of this Code.

(4) The wind design loads for any fabric or membrane covered structure designed with a permanent or non-removable fabric or membrane, shall be based on the following criteria:

(aa) Minimum wind velocity of 110 m.p.h.
(bb) Importance factor based on Category IV, I = 1.0
(cc) Velocity pressure coefficient, Kz - Use Exposure "B" for all applications except that Exposure "D" shall be used for installations within the coastal construction zone as defined by Section 2302 of this Code.<<



_ [[MINIMUM SIZE OF FRONT BARS
3' width between supports.................................................................................................
1/2" pipe

9' width between supports.................................................................................................
3/4" pipe

14' width between supports................................................................................................
1" pipe

_
_EXTENSIONS ON AWNINGS AND TRUSS SUPPORTS
Rafters up to 5'-0" in extension from supporting wall .......................................................
1/2" pipe

Rafters up to 9'-0" in extension from supporting wall .......................................................
3/4" pipe

Rafters up to 12'-0" in extension from supporting wall .....................................................
1" pipe

Rafters on canopies shall be not more than 5'-0" apart.





-_NUMBER OF SUPPORTS REQUIRED OF ROLLER-GEAR AWNINGS
Up to 20'-0" in width parallel to supporting wall..................................................
no center support

20' to 30'-0" in width parallel to supporting wall ..................................................
1 center support

30' to 50'-0" in width parallel to supporting wall ..................................................
2 center supports

50' to 60'-0" in width parallel to supporting wall ..................................................
3 center supports

60' to 70'-0" in width parallel to supporting wall ..................................................
4 center supports

_
_ NUMBER OF ARMS REQUIRED FOR ROLLER-GEAR AWNINGS
Length of Awning
Quantity

Up to and including 20'-0".............................................................................................
2 arms

Up to and including 30'-0".............................................................................................
3 arms

Up to and including 40'-0".............................................................................................
4 arms]]


-4305.3 (b) The [[cloth]] >>fabric<< parts of awnings >>, FCF<< and canopies shall be securely laced, tied or otherwise fastened to the frame; no rafter or front bar will be permitted in pockets; and in no case shall a rolling curtain be caused to operate over a canopy frame.

[[(c) The front bar of an awning, when pulled up, shall not be higher than the head of the awning.

(d) The awning head bar may be of wood, provided such wood is treated to resist rot and weather deterioration.


(e) When attaching awnings of canopies to masonry walls or columns, lags and expansion bolts in metal shield shall be required. Wood plugs are hereby prohibited. Fastenings shall be not less than 3/8" bolts, nor more than 3' - 0": apart.]]

(>>c<<) (1) The horizontal projection of cantilevered portions shall not be greater than 2 times the height, except where the building construction does not permit a proper installation; in which case, variance may be permitted by the Building Official, based on special design and construction.

[[(2) All fabric awnings except roller-gear awnings with folding arms, must be equipped with fire chains, one end of which fastens to the front bar or side arm. not more than 6" back of the front bar and the other end of which fastens to a point just under the head bar, but not to the head bar or head-bar fastenings.

(3) Such chains and fastenings shall be of sufficient strength to withstand the stress of the awning's being dropped and to keep the frame from going below the required minimum.]]

-4306 _[[TENTS]] >>TEMPORARY STRUCTURES

The provisions of this section shall apply to tents, membrane structures and other habitable structures erected for a period of less than 180 days:<<

-[[4306.1_ No profit-seeking or commercial activity of any kind or character whatsoever shall may be transacted within an area covered by a tent temporary structure, except Temporary commercial activity or a traveling organization regularly employing such a tent or membrane structure as means of weather protection, such as a circus, or a convention, seasonal events or a religious revival may be temporarily permitted within an area covered by a temporary structure.]]

-4306.[[2]]>>1<< (_>>a)<< Tent>>s or membrane structures<< may not be used for general storage of any character whatsoever>>. Tents or membrane structures<< may not be used for sleeping purposes., except as temporary shelter in connection with camping trips, outings for youth organizations, and other similar uses or where necessary to accommodate individuals in emergency situations.

(b) Tents or membrane structure use exclusively for recreational purposes or less than 120 sq. ft. shall be exempted from obtaining a permit.<<

-4306.[[3]]2_ (a) All fabric, curtains, cloth, rope, netting and decorative material used for, or in, or on, a tent >>or membrane structure<< shall be rendered flameproof [[provided that flame-proofing will not be required for tent open on one side and with standing capacity only for 20 or less persons]].

(b) [[Tent required to be of flame-proofed material shall be inspected by the Building Official and the flame-proofing certified on the Application for Building Permit, issued for the erection of such tent.]] >>All tent fabric shall meet the requirements of the large scale test contained in NFPA 701, Standard Methods of Fire Tests for Flame-Resistant Textiles and Films.<<

4306.4>>3<<(a) All tents >>and membrane structures<< shall be constructed and erected to withstand a wind pressure >>or suction<>in accordance with NFPA 102.<<

(b) >>The poles and their supporting guys, stays, stakes, and fastenings shall be of sufficient strength to resist a minimum wind pressure of 20 psf of projected area of the tent in accordance with NFPA 102.<<

([[b]]>>c)<< No tier of seats shall rise to a height exceeding 12'-0".

([[c]]>>d<<) All lighting shall be by electricity.

([[d]]>>e<<) A minimum of 2 exits shall be provided where a tent >>or membrane structure<< is used as a place of assembly [[for]] >>of<< 100, or more, persons.

([[e]]>>f<<) Where tents are used as a place of assembly, with a capacity of 500 or more persons, each exit shall be not less than 9'-0" wide; and the number of exits shall be one additional exit for each additional 500 persons, or major fraction thereof.

([[f]]>>g<<) Exits shall be spaced no more than 75'-0" apart.

([[g]]>>h<<) Aisles shall not be less than 44" in width, provided such aisles shall not be less in width than the combined width of aisle that they connect.

(hi) There shall be not more than 10 seats between any seat and aisle, and if the seating capacity of such tent exceeds 500 persons, collapsible chairs shall be fastened together in banks of 10.

-4306.[[5]]>>4<<_ [[Tent shall not be less than 30'-0" from side or rear property lines or from other buildings on the same property. No tent shall be erected in Fire Zone I.]]

>>Construction documents: A permit application and construction documents shall be submitted for each installation of a temporary structure. The construction documents shall include a site plan indicating the location and size of the temporary structure and information delineating the means of egress and the occupant load.

4306.>>[[6]] >>5 Location: All temporary structures shall be located in accordance with the requirements of this code based on the fire resistance rating of the exterior walls for the proposed type of construction.

4306.<<[[7]]>>6 Construction: Tents and air supported structures shall be constructed as required by this code and NFPA 102.

4306.8 7 Membrane material: The membrane material for all tents shall be of approved non-combustible material as defined in Section 401, flame resistant material as determined in accordance with both the small-scale and large-scale tests in NFPA 701 or material treated in an approved manner to render the material flame resistant.

4306.9 8 Certification: An affidavit or affirmation shall be submitted to the code official and a copy retained on the premises on which the tent or air-support structure is located. The affidavit shall attest to the following information relative to the flame resistance of the fabric:

(1) Names and addresses of the owners of the tent or air-supported structure.

(2) Date the fabric was last treated with flame resistant solution.

(3) Trade name or kind of chemical used in treatment.

(4) Name of person or firm treating the material.

(5) Name of testing agency and test standard by which the fabric was tested.

4306.<<[[10]]>>9Inflation pressure: Operating pressure shall be maintained at the design pressure specified by the manufacturer to assure structural stability and to avoid excessive distortion during high wind.

4306.<<[[11]]>>10 Door operation: In high winds, the doors in air supported structures shall be controlled to avoid excessive air loss. Doors shall not be left open under any conditions.

4306.<<[[12]]>>11Means of egress: All temporary structures including tents and membrane structures shall conform to the means of egress requirements of Chapter 31 and shall have a maximum exit access travel distance of 100 feet (30480 mm).

4307 MEMBRANE STRUCTURES

4307.1 GENERAL

(a) PURPOSE: The purpose of this section is to establish minimum standards of safety for the construction and use of air-supported, air-inflated and membrane-covered cable or frame structures, collectively known as membrane structures.

(b) SCOPE: The provisions of this section shall apply to membrane structures erected for a period of 180 days or longer. Those erected for a shorter period of time shall comply with applicable provisions in section 4306.

EXCEPTION: Water storage facilities, water clarifiers, water treatment plants, sewer plants, agricultural greenhouses and similar facilities not used for human occupancy need meet only the requirements of paragraph 4307.2(b) and sub-section 4307.5 of this code.

4307.2 TYPE OF CONSTRUCTION AND GENERAL REQUIREMENTS:

(a) GENERAL: Membrane structures shall be classified as Type V Construction, except that non-combustible membrane structures may be classified as Type II Construction.

EXCEPTION: A non-combustible membrane structure used exclusively as a roof and located more than 20 feet above any floor, balcony or gallery is deemed to comply with the roof construction, provided that such a structure complies with the requirements of this section.
(b) MEMBRANE MATERIAL: Membranes shall be of non-combustible material as defined by Section 401 of this Code.
(c) APPLICABILITY OF OTHER PROVISIONS: Except as specifically otherwise required by this section, membrane structures shall meet all applicable provisions of this Code. Roof covering shall be fire retardant.
EXCEPTION: Roof coverings for Group J, Division 1 and 7 Occupancies not exceeding 1,000 square feet in area need not be fire retardant.
(d) ALLOWABLE FLOOR AREAS: The area of a membrane structure shall not exceed the limits set forth in the requirements of the respective Occupancy Group, except as provided in Chapter 5.
(e) MAXIMUM HEIGHT: Membrane structures shall not exceed one story nor shall they exceed the height limits in feet set forth in the requirements of the respective Occupancy Group.
EXCEPTION: Non-combustible membrane structures serving as roof only.
4307.3 INFLATION SYSTEMS:
(a) GENERAL: Air-supported and air-inflated structures shall be provided with primary and auxiliary inflation systems to meet the minimum requirements of this section.
(b) EQUIPMENT REQUIREMENTS: The inflation system shall consist of one or more blowers and shall include provisions for automatic control to maintain the required inflation pressures. The system shall be so designed as to prevent over pressurization of the system.
In addition to the primary inflation system, in buildings exceeding 1,500 square feet in area, there shall be provided an auxiliary inflation systems with sufficient capacity to maintain the inflation of the structure in case of primary system failure.
The auxiliary inflation system shall operate automatically if there is a loss in internal pressure or should the primary blower system become inoperative.
Blower equipment shall meet the following requirements:
(1) Blowers shall be powered by continuous rated motors at the maximum power required for any flow condition as required by the structural design.
(2) Blowers shall be provided with inlet screens, belt guards and other protective devices as may be required by the Professional Engineer to provide protection from injury.
(3) Blowers shall be housed within a weather-protecting structure.
(4) Blowers shall be equipped with back draft check dampers to minimize air loss when operative.
(5) Blower inlets shall be located to provide protection from air contamination. Location of inlets shall be by the Professional Engineer.
(c) EMERGENCY POWER: Whenever an auxiliary inflation system is required, an approved standby power-generating system shall be provided. The system shall be equipped with a suitable means for automatically starting the generator set upon failure of the normal electrical service and for automatic transfer and operation of all the required electrical functions at full power within 60 seconds of such normal service failure, Standby power shall be capable of operating independently for a minimum of four (4) hours.
4307.4 SECTION PROVISIONS:
(a) A system capable of supporting the membrane in the event of deflation shall be provided in all air-supported and air-inflated structures having an occupant load of more than 50 people or when covering a swimming pool regardless of the occupant load. Such system shall maintain at least seven (7) feet above the floor, seating area or surface of the water.
EXCEPTION: Membrane structures used as roof for Type I and II Fire Resistant Construction shall be maintained not less than twenty five (25) feet above floor or seating areas.
4307.5 ENGINEERING DESIGN:
(a) All membrane structures shall be structurally designed in accordance with the criteria developed by a Professional Engineer.
(b) All membrane structures shall meet all of the impact and cyclic loading requirements as provided for in Chapter 35 of this Code and the wind loads with the applicable factors and the live and dead loads as provided for in Chapter 23 of this Code, except that the deflection limitation of the impact test shall not apply.<<



>>APPENDIX "G"

BUILDING CODE COMMITTEE COMMENTARY ON

CHAPTER 43


1. GENERAL:

Fabric Covered Framework (FCF) is considered to be appurtenances of limited life, assembled, erected or installed mainly to provide everyday weather protection, and/or for aesthetic value or architectural enhancement. Past history in South Florida shows that FCF does not represent a hazard to human life, even after being damaged by severe wind activity. Actually, failure of fabric and distortion of framework by hurricane winds may never become a significant threat to public welfare as long as framework remains attached in place.

FCF must be of designs, materials, proportions, durability and resistance to forces and strains, as set forth in Chapter 43.

FCF are classified by industry based on the kind of fabric installation, as follows:

FCF of non-detachable fabric
FCF of detachable or removable fabric
Retractable FCF
FCF installed for a limited time (tents)
Commercial interior FCF (exposed to no wind loads)

FCF as such, may be designed, assembled or fabricated of multiple shapes, styles, and proportions for a variety of applications, such as awnings, staple-on systems, back-lit or illuminated awning signs, canopies, carports, marquees, domes, cabanas, roller curtains, tents, etc., etc.

2. Materials

(a) Fabrics, as used in today's FCF are of a great variety of relatively complex intertwined natural and synthetic materials, of the most diverse textures and qualities. The fabric manufacturers as well as the FCF industry, conventionally refer to a 10.10 oz. army duck as the minimum acceptable fabric. However, this type of fabric is not recommended for areas of constant high humidity (such as Dade County) due to its cotton base. Among the many of primary generic fabrics used in today's FCF, the following list may include most of the recognizable groups:

Painted Army Duck Solution Dyed Modacrylic
Solution-Dyed Acrylic Vinyl Laminated Polyester
Vinyl Coated Poly Cotton Blend Yarn Coated Polyester
Vinyl Coated Cotton
Vinyl Coated Polyester

All such fabrics are intrinsically biodegradable which results in a continuous loss of their structural strength from the first day of installation. Equally degradable are the miscellaneous components used with these fabrics, such as: threads, cords or ropes for lacing, heat-welded seams, trims, etc.. In general, fabric manufacturers refer to these generic fabrics' durability as averaging life spans between 5 and 8 years, depending on climate and proper care of fabrics.

Fabric's structural strengths (tensile, bursting, tearing, etc.) are typically reported for new unexposed samples; sometimes, with an indication of the unpredictable range of strength retained for one-half year intervals of continuous use and exposure to climate. Such strength retained values may reduce to a fraction (80%+ to 50%-) of the original strength in just 12 months of continuous exposure. Similarly, test results on nylon and polyester threads, the most commonly used in FCF, indicate that the average range (in percentage) of strength retained during continuous exposure in Florida are 51% (80% to 32%) after the first six months; 28% (47% to 15%) after a 12-month period; and 14% (22% to 5%) after a 24-month period. Obviously, the nominal durability of fabrics (as referred to by fabric manufacturers) is meaningless with respect to fabric's strength as an actual structural parameter.

In general, the weight of generic fabrics (ranging from 9.5 to 22 oz. per sq. yd.) may be assumed to correlate with their corresponding original durability and strength; but such values vary for each generic group of fabrics.

Fabrics used for any purpose herein defined must be flame resistant in accordance to NFPA 701. Fabrics for tents must be flame-resistant.

FCF structural and support systems must be formed of metal or materials of similar strength and durability. The following generic materials most commonly used in the FCF fabrication are:

Steel Pipe - (ASTM A120, ASTM A53E, ASTM A53S)
Mild Steel Tubing - (ASTM A513 Type 1, ASTM A135, AISI 1018, AISI 1020)
Aluminum Tubing - (6061-T6, 6063-T6, 6063-T5)
High Strength Coated Tubing, Cold Formed (ASTM A500, Grade B)
Stainless Steel Tubing (AISI Type 304)

Connectors, attachments, fasteners, and fittings in general, must be of metal or other approved materials, either of a greater strength than the base material of the structural support system.<<


Section 2. If any section, subsection, sentence, clause or provision of this ordinance is held invalid, the remainder of this ordinance shall not be affected by such invalidity.

Section 3. This ordinance does not contain a sunset provision.

Section 4. It is the intention of the Board of County Commissioners, and it is hereby ordained that the provisions of this ordinance shall become and be made a part of the South Florida Building Code. The sections of this ordinance may be renumbered or relettered to accomplish such intention, and the word "ordinance" may be changed to "section," "article," or other appropriate word.

Section 5. This ordinance shall become effective July 1, 1997 unless vetoed by the Mayor, and if vetoed, shall become effective only upon an override by this Board.
Words stricken through and/or [[double bracketed]] shall be deleted. Underscored words and/or >>double arrowed<< constitute the amendment proposed. Remaining provisions are now in effect and remain unchanged.