1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULSeptember 24, 20091SUBJECT 2218AOUTLINE OF INVESTIGATIONFORIMPACT RESISTANCE OF ROOFING SYSTEMSISSUE NO: 1September 24, 2009Summary of TopicsThis is the first issue of the Outline of Investigatio
2、n for Impact Resistanceof Roofing Systems, Subject 2218A. This test method provides impactresistance data for the evaluation of low slope roofing systems . Forpurposes of this standard, roof systems consist of various componentmaterials installed on combustible or noncombustible decking intendedfor
3、installation on roofs with an incline which is 14 (25 % or 3 in/ft) orless.COPYRIGHT 2009 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULSEPTEMBER 24, 2009SUBJECT 2218A2No Text on This PageUL COPYRIGHTED MATERIAL
4、 NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .42 Units of Measurement .4PERFORMANCE3 General 44 Preparation of Samples 44.1 General .44.2 Preparation of test decks 54.3 Application .54.4 Conditioning .55 Test Apparatus .56 Test Procedu
5、re .67 Acceptance Criteria .6REPORT8 General 69 Classes of Prepared Roof Coverings for Impact Resistance 7APPENDIX AA1 General .A1SEPTEMBER 24, 2009 SUBJECT 2218A 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 This tes
6、t method provides impact resistance data for the evaluation of low slope roofing systems . Forpurposes of this standard, roof systems consist of various component materials installed on combustibleor noncombustible decking intended for installation on roofs with an incline which is 14 (25 % or 3 in/
7、ft)or less.1.2 The test evaluates the effect of impact from the steel ball at locations on the assembly selected to bemost vulnerable, such as (but not limited to) edges, corners, unsupported sections and joints.1.3 This test method does not evaluate the effect of weathering, temperature, aging or s
8、imilar effects onthe impact resistance of roofing system components. These and other factors, including time, roof slope,roof system configuration and application influence the performance of roofing materials in the field. It isnot the objective of this test to address all of these factors.2 Units
9、of Measurement2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.PERFORMANCE3 General3.1 Representative samples of the roof system construction, assembled to test decks as described inPreparation of Samples, Section 4, are to be
10、 subjected to the impact tests described in Test Apparatus,Section 5, and Test Procedure, Section 6.4 Preparation of Samples4.1 General4.1.1 Representative samples of a roof system are to be applied, as described in 4.3, to test decksconstructed as described in 4.2. The assemblies are to be conditio
11、ned in accordance with 4.4 prior totesting.SEPTEMBER 24, 2009SUBJECT 2218A4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL4.2 Preparation of test decks4.2.1 The test decks are to be 3 ft by 3 ft (0.91 m by 0.91 m) consisting of 15/32 in (11.9
12、 mm) thickplywood securely nailed to a trade size 2- by 4-in nominal 1-1/2 by 3-1/2 in (38.1 by 89 mm) wood battenframe, with an additional trade size 2- by 4-in vertical support batten, midspan of the deck. The plywoodis to be PS-1 Grade exterior, placed A side up. The perimeter battens are to be l
13、ocated under and flushwith the outer edges of the deck.4.3 Application4.3.1 The roof covering material to be tested is to be applied in accordance with the manufacturersinstructions to the test deck. The material is to extend to and be flush with the edges of the deck.4.4 Conditioning4.4.1 The test
14、assemblies are to be stored indoors at a temperature of 73.4 3.4F (23.0 1.8C) for theperiod of time necessary to cure the material; or stored under other conditions until moisturedeterminations indicate that the deck lumber has a maximum 12 percent moisture content. Test decks areto be stored so tha
15、t each will be surrounded by freely circulating air.5 Test Apparatus5.1 The test apparatus shall be as described in the Standard for Impact Resistance of PreparedRoof-covering Materials, UL 2218, Section 5, Test Apparatus, and in accordance with the steel balldiameters and drop heights shown by Tabl
16、e 5.1 below.Table 5.1Drop height and kinetic energyClass Steel ball diameter Distance Kinetic energyInches (mm) Feet (m) ft-lbf (J)1 1-1/4 (31.8) 12.0 (3.7) 3.53 (4.78)2 1-1/2 (38.1) 15.0 (4.6) 7.35 (9.95)3 1-3/4 (44.5) 17.0 (5.2) 13.56 (18.37)4 2 (50.8) 20.0 (6.1) 23.71 (32.12)SEPTEMBER 24, 2009 SU
17、BJECT 2218A 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL6 Test Procedure6.1 Tests are to be conducted in a room at a temperature of 73.4 3.4F (23.0 1.8C). Each testassembly is to be subjected to a series of two coincident drops from a spe
18、cific size steel ball at each ofsix locations selected based upon examination for vulnerability. These locations are to include but not belimited to edges, corners, unsupported areas, overlaps and joints. The drop shall be considered coincidentwhen the approximate center of the impact depression of
19、the second drop is measured to be within 1/2in (12.7 mm) of the first.6.2 After the first drop at each location, the resultant depression is to be measured and recorded to thenearest 0.01 in (0.25 mm) using a depth gauge. After the assembly has been subjected to all drops at theselected impact locat
20、ions the roofing system is to be carefully examined on the top surface at theimpacted areas. Multiple layers/components of the roofing system located under the impacted area are tobe examined separately.6.3 Visual damage observations are to be facilitated by examining the samples under 5X magnificat
21、ionand the observations recorded for each impact location, based upon the acceptance criteria in Section 7and the report information specified in Section 8.7 Acceptance Criteria7.1 The roofing system is to be examined after being subjected to the test procedure described in Section6, Test Procedure.
22、 The roofing system exposed surface shall show no evidence of tearing, fracturing,cracking, splitting, rupture, crazing or other evidence of opening.REPORT8 General8.1 The report shall include the following:a) Description of the sample preparation and deck construction;b) Description of the sample;c
23、) Sample conditioning procedure;d) Size of steel ball and impact locations;e) Observations and measurements of each impact location, including:1) Depth of depressions, when depressions occur, following the single impacts.2) Any tearing, fracturing, cracking, splitting, rupture, crazing, or other evi
24、dence ofopening of the roofing system outermost layer.3) Under layers/components examined for any tearing, fracturing, cracking, splitting,rupture, crazing, or other evidence of damage to the roofing system.4) Any chipping or spilling of concrete tile or fiber cement roofing systems.f) Determination
25、 of pass or fail.SEPTEMBER 24, 2009SUBJECT 2218A6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL9 Classes of Prepared Roof Coverings for Impact Resistance9.1 Prepared roof coverings evaluated in accordance with this method are of the followin
26、g four classes(also as shown in Table 5.1):a) Class 1 Passes acceptance criteria of 1-1/4 in diameter ball.b) Class 2 Passes acceptance criteria of 1-1/2 in diameter ball.c) Class 3 Passes acceptance criteria of 1-3/4 in diameter ball.d) Class 4 Passes acceptance criteria of 2 in diameter ball.SEPTE
27、MBER 24, 2009 SUBJECT 2218A 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULSEPTEMBER 24, 2009SUBJECT 2218A8No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULAPPENDIX
28、AA1 GeneralA1.1 This Appendix provides historical explanation describing where the values for steel ball diameters,drop heights and kinetic energies are derived from and how they are relevant to impacts from hail.A1.2 The following values in Table A1 were derived from the impact energy of hailstones
29、 graphed byJ.A.P. Laurie in 19601. Laurie graphed the relationship between hailstone terminal velocity, hail diameter,and the approximate kinetic (impact) energy as shown below.Table A1Terminal velocities and energies of hailstones standard test methodsDiameter Terminal velocity Approximate impact e
30、nergyinches (cm) ft/s mi/hr (m/sec) Ft-lbs Joules1 (2.5) 73 50 (22.3) 1 (1.36)1-1/4 (3.2) 82 56 (25.0) 4 (5.42)1-1/2 (3.8) 90 61 (27.4) 8 (10.85)1-3/4 (4.5) 97 66 (29.6) 14 (18.96)2 (5.1) 105 72 (32.0) 22 (29.80)2-1/2 (6.4) 117 80 (35.7) 53 (71.9)2-3/4 (7.0) 124 85 (37.8) 81 (109.8)3 (7.6) 130 88 (3
31、9.6) 120 (162.7)A1.3 Using these relationships, UL developed an impact test method with the same diameter steelspheres dropped at heights to achieve the same approximate impact energy shown. The heights werecalculated based on the equivalent potential energy that would result in the needed impact en
32、ergy.A1.4 In developing this method, it was recognize that the effect of weathering, temperature, aging, timeof impact roof slope and installation influence effects on the impact resistance of prepared roof coveringmaterials vary greatly and would not be considered as a part of this product comparit
33、ive test method.A1.5 Precision and Bias Statement While this basic method has been used since the mid 1990s, thereis currently no documented inter-laboratory Precision and Bias for this test method.1Laurie, J.A.P., “Hail and its Effects on Buildings,” Research Report No. 176, NBRI, Pretoria, South Africa,August 1960.SEPTEMBER 24, 2009 SUBJECT 2218A A1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULSEPTEMBER 24, 2009SUBJECT 2218AA2No Text on This Page
