1、Designation: C 1570 03Standard Test Method forWind Resistance of Concrete and Clay Roof Tiles(Air Permeability Method)1This standard is issued under the fixed designation C 1570; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 The air permeability of tile roofing systems is a criticalfactor in determining the wind resistance of tile r
3、oofing asapplied to a roof. This Standard describes a procedure formeasuring the air permeability of clay and concrete tile andslate roof systems when applied to a small section of roof deckin accordance with the manufacturers instructions.1.2 This test procedure measures the air permeability of ala
4、id array of unsealed clay or concrete roof tiles or slates. Thetiles or slates shall have a thickness between18-in. (3-mm) and2-in. (51-mm).1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard t
5、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:C 43 Terminology of Structural Clay Products2C 67 Test Methods for Sampling and Testing Brick andStructural Clay Tile2C 140 Test Meth
6、ods of Sampling and Testing ConcreteMasonry Units2C 1167 Specification for Clay Roof Tiles2C 1492 Specification for Concrete Roof Tiles22.2 SBCCI Standard:SBCCI SSDT 11, SBCCI Test Standard for DeterminingWind Resistance of Concrete or Clay Roof Tiles3NOTE 1This standard is based on the Internationa
7、l Code CouncilsICC/SBCCI SSTD 11 and work derived from the tile industrys testingprograms completed in the Redland Wind Tunnel in the UK.2.3 ASCE Standard:ASCE 7, Minimum Design Loads for Buildings and OtherStructures43. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod refe
8、r to Terminology C 43, and Specifications C 1167and C 1492.4. Principle of the Test Method4.1 Air pressure is applied to the underside of an airpermeable assembly of a specified type of roofing elements.The difference in air pressure across the assembly and thevolume air flow rate are measured and u
9、sed to determine the airpermeability of the assembly.5. Significance and Use5.1 The air permeability of roofing systems constructedfrom discrete elements, as is the case for clay and concrete tileand slate roof systems, is a critical factor in determining thewind resistance of the roof system. The a
10、bility of the roofsystem to relieve wind-induced uplift pressures as a result ofthe overall air permeability of the roof assembly relates to theresistance of the roof system to damage induced by wind.5.2 Natural wind conditions differ with respect to intensity,duration, and turbulence; these conditi
11、ons are beyond themeans of this test method to simulate.6. Apparatus6.1 A plenum chamber is a rectangular box with a depth ofnot less than 1.64 ft (500 mm) or one-third of the least lateraldimension, whichever is the greater. The plenum chamber shallbe made airtight except for an open upper face to
12、receive amounting board or cover panel, a tapping for a pressuredifference gage (relative to atmospheric pressure) and a con-nection to an air delivery pipe. The tapping shall be positionedto avoid direct alignment with the air delivery pipe. The shapeand area of the mounting surface shall be capabl
13、e of accepting1This test method is under the jurisdiction of ASTM Committee C15 onManufactured Masonry Units and is the direct responsibility of SubcommitteeC15.06 on Roofing Tile .Current edition approved August 10, 2003. Published August 2003.2Annual Book of ASTM Standards, Vol 04.05.34Available f
14、rom The American Society of Civil Engineers (ASCE), 1801Alexander Bell Dr., Reston, VA 20191.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the number of test samples specified in 8.1 as a minimum. Aschematic of the air permeability
15、 apparatus is shown in Fig. 1.6.2 An airtight removable cover panel shall be securedairtight to the plenum chamber.6.3 An open face mounting board to receive the roofingsubstrate and test samples.6.4 A controllable air flow generator shall be capable ofcontinuously delivering air at a rate such that
16、 the upliftoverturning moment on the roofing elements induced by thepressure in the plenum chamber by the air flow is equal andopposite to the dead weight restoring moment.6.5 An airflow meter capable of measuring air volume flowrates in the delivery pipe and having an accuracy of 0.1 ft3/s(0.003 m3
17、/s) or better.6.6 A pressure difference measuring device (such as amanometer) connected to the inside and outside of the plenumchamber, capable of measuring a pressure difference of not lessthan 0.15 psi (1000 Pa).6.7 Airtight seals for pipe connections, mounting board andcover panels, and at joints
18、 and edges of the roofing assembly.6.8 A weighing device capable of measuring the deadweight of the roofing elements to the nearest 0.1 lbm (0.05 kg).7. Check on Air-tightness of the Apparatus7.1 Close the top of the plenum chamber by attaching andsealing the edges of the mounting board or cover pan
19、el so thatthe plenum chamber is air-tight except where connected to thedelivery pipe.7.2 Supply air from the airflow generator to induce apressure difference between the inside and outside of theplenum chamber at test pressure but not less than 10.5 lbf/ft2(500 Pa). The air tightness of the plenum c
20、hamber shall beconsidered satisfactory if this pressure difference is maintainedwith an air flow-rate not exceeding 0.15 ft3/s (0.004 m3/s).8. Test Specimen8.1 Select, at random, sufficient roofing elements and halfwidth elements, where appropriate, to assemble an array witha minimum of 4 unsealed e
21、lements. Roofing elements forcovering the perimeter of the mounting board shall be providedand are to be air-sealed at their appropriate laps, front and sidejoints.NOTE 2A typical array illustrated for tiles or slates is shown in Fig. 2.This shows 5 unsealed tiles (5 unsealed headlaps and 5 unsealed
22、 sidelaps).8.2 Provide sufficient roof element fastening systems, whereappropriate.8.3 Provide sufficient roof substrate materials, such asbattens and their fasteners.9. Determination of the Critical Uplift PressureDifference, Dpc, lbf/ft2(Pa)9.1 Weigh each of the roofing elements in the air-drycond
23、ition.9.2 Calculate the average weight (wt), lbm (kg), of a roofingelement.9.3 Calculate the upward pressure difference, Dpc, which isthe critical pressure drop which will just fail to lift an array ofunfixed samples from:Dpc5 0.9 $wtLg/ bgaLu!% (1)where:Lg= distance, ft (m), from the center of grav
24、ity of thesample to its uppermost line of support or the top edgeof the batten,b = exposed width, ft (m), of the roof tile or slate,ga= batten gage, ft (m) which is also the exposed length ofthe tile, andLu= distance, ft (m), from the center of the exposed area ofthe sample to its uppermost line of
25、support or the topedge of the batten.10. Preparation of the Test Assembly10.1 Construct the roof substrate without underlayment,underlayment for spaced sheathing, or sheathing boards. Bat-tens shall be laid across the rafters to provide support for theelements. Battens shall be used without sheathin
26、g to providesupport for the elements regardless of the roof construction,direct deck or batten construction. Where the element may belaid to different gages and the test is to be carried out on onlyone gage, set out to the maximum specified gage.10.2 Lay and secure the roofing elements. For doublela
27、pped elements, lay elements with no gap between adjacentelements. For single lap elements, lay elements with maximumsidelap in order to produce the minimum exposed width. It isnot necessary to secure the elements with clips unless these areessential to maintain appropriate headlap/sidelap gaps.10.3
28、Seal against air leakage between peripheral elements tomounting board and to each other on all sides.10.4 Adjust the level of the plenum chamber such that themounting board surface is at 100 to the horizontal (612).10.5 Determine the effective area A,ft2(m2), of the roofingelement assembly under tes
29、t from the formula:A 5 NBga(2)FIG. 1 Air Permeability Test ApparatusC1570032where:N = number of unsealed roofing elements under test,b = exposed width of the roof tile or slate, ft (m), andga= batten gage, ft (m), which is also the exposed length ofthe tile.11. Procedure11.1 Check the air-tightness
30、of the apparatus in accordancewith Section 7.11.2 Supply air from the airflow generator into the plenumchamber, gradually increasing the rate of supply until thepressure reaches a value equal to Dpc. See Eq 1 in 9.3.11.3 When the pressure equals Dpc, record the volume flowrate Qc,ft3/s (m3/s), in th
31、e delivery pipe and the pressuredifference in the plenum chamber Dpc, lbf/ft2(Pa). Graduallyreduce the pressure difference to zero.11.4 Repeat the test procedure three times and calculate theaverage value of the air permeability (Cd) from the three testsusing the formula:Cd5QcA12 Dpcgr(3)where:r = d
32、ensity of air, lbm/ft3(kg/m3),g = acceleration due to gravity, ft/s2(m/s2), andA = effective area of the roofing assembly, from Eq 2 in10.5, ft2(m2).12. Criterion for Uplift Coefficient12.1 For an uplift coefficient, CLof 0.20 the average valueof the air permeability (Cd), shall be greater or equal
33、to 3 3103.13. Report13.1 The test report shall include:13.1.1 The type, name, and dimensions of product,13.1.2 Details of laps and any mechanical fastening system,where appropriate,13.1.3 Details of the test apparatus,13.1.4 A plan of the roofing assembly tested, indicatingsealed and unsealed elemen
34、ts,13.1.5 Calculated values of over-turning moment (upliftforce) and critical upward pressure difference (Eq 1) to twosignificant figures,13.1.6 Air volume flow rate at each of the pressure differ-ence readings,13.1.7 Date when the test was performed, and13.1.8 Location where the test was performed.
35、FIG. 2 Plenum Chamber Arrangement for Air Permeability TestC157003314. Precision and Bias14.1 PrecisionIt is not possible to specify the precision ofthe procedure for measuring air permeability because theapparatus is unique and has been used for an insufficientnumber of tests to allow calculation o
36、f precision.14.2 BiasNo information can be presented on the bias ofthe procedure in Test Method C 1570 for measuring airpermeability because no material having an accepted referencevalue is available.15. Keywords15.1 air permeability method; clay roof tile; concrete rooftile; critical upward pressur
37、e difference; uplift resistance; windresistanceASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights,
38、and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revi
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40、shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C1570034
