1、STD-CGSB 149.L5-9b-CAN/CGSB-FREN 1874650 0033682 2BT 3 t .i CAN/CGSB-149.15-96 AMENDMENT NO. i MODIFICATIF N“ 1 AprilAvril 1999 % fi$ / CANADIAN GENERAL STANDARD BOARD OFFICE DES NORMES GENERALES DU CANADA DETERMINATION OF THE OVERALL THE FAN PRESSURIZATION METHOD USING DETERMINATION DE LTANCHIT A L
2、AIR LA MTHODE DE DEPRESSURISATION PAR ENVELOPE AIRTIGHTNESS OF BUILDINGS BY THE BUILDINGS AIR HANDLING SYSTEMS GLOBALE DES ENVELOPPES DE BTIMENTS PAR VENTILATEUR AU MOYEN DES SYSTMES DE TRAITEMENT DAIR DES BTIMENTS Add the following new Appendix F: Ajouter la nouvelle annexe F qui suit: Copyright Ca
3、nadian General Standards Board Provided by IHS under license with CGSBNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-F1 . F2 . F3 . F4 . F5 . F6 . F7 . F8 . F9 . APPROACHES FOR DETERMINING AIR LEAKAGE CHARACTERISTICS OF BUILDINGS TABLE OF CONTENTS BACKGROUND . F2
4、COMMENTARY F3 PREFACE F3 SCOPE AND FIELD OF APPLICATION . F5 PRINCIPLE . REFERENCED PUBLICATIONS . F8 TERMINOLOGY . F9 APPARATUS F9 CALIBRATION OF TEST APPARATUS . F9 TESTING . F9 CALCULATIONS . f14 TEST REPORT F14 ATIACHEMENT A: DATA SHEETS F15 CAN/CGSB-149.15-96 F1 Copyright Canadian General Stand
5、ards Board Provided by IHS under license with CGSBNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD-CGSB 149oLS-Sb-CAN/CGSB-FREN 1874650 0033b84 OS2 W rt y BACKGROUND r Air leakage into and out of a building occurs mainly through unintentional openings, such as c
6、racks formed at the joints of various envelope components. The size of the envelope leakage area of a building is a key factor in determining the magnitude of the air infiltration and exfiltration rates across the building envelope due to stack effect and wind. The pressure differences and uncontrol
7、led air leakage can cause several problems including the following: - - condensation; - - - unbalanced performance of air distribution systems; cold drafts and comfort problems; interference with proper operation of entrance doors, elevator doors and some types of smoke control systems; and much lar
8、ger heating loads and high energy consumption. Knowledge of the air leakage characteristics of a building envelope is required to prevent undesirable air movement, to ensure efficient performance of the air handling systems, and to reduce the energy consumption. Over the years, the building. shell c
9、onstruction practices have changed significantly with regards to airtightness. The 1995 National Energy Code for Buildings stipulates the requirements for the minimum air leakage performance of the building envelopes. Recent demonstrations of low energy commercial buildings, such as IDEAS Challenge
10、by CMHC and the C-2 Program by NRCan. are targeted to meet certain airtightness criteria. To address the various building airtightness requirements in new construction and the retrofits of existing buildings, a CGSB standards committee was formed to provide standardized test procedures and standard
11、methods for measuring air leakage characteristics. The CGSB standard CANKGSB-149.15-96 deals with a test procedure to determine the overall building envelope airtightness of buildings by fan pressurization or depressurization using the buildings air handling systems. A need for an accompanying comme
12、ntary for the standard was identified by the CGSB committee due to the wide variety of buildings and building air handling systems, and the complexity of test procedures. The Commentary section provides explanations of various clauses of the standard as well as guidance on practical approaches that
13、will be required to undertake testing of buildings. F2 CAN/CGSB-149-15-96 Copyright Canadian General Standards Board Provided by IHS under license with CGSBNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SfD*CGSB L49=LS-Sb-CAN/CGSB-FREN M L874b50 O033685 T99 m COMM
14、ENTARY SECTION CGSB standard CANICGSB-149.15-96 - Determination of the Overall Envelope Airtightness of Buildings by t ization Method Using the Buildings Air Handling Sys COMMENTARY The CGSB standard CAN/CGSB-149.15-96 can be used to determine the airtightness of the entire building envelope or the
15、enclosed test section of the building. The buildings ventilation system is used for pressurizing or depressurizing the test volume. The airtightness tests can be conducted for the whole building volume or any part of the building. The test results can provide the airtightness values for building env
16、elope. It should be noted that this method does not directly determine the quantity of actual air leakage, which occurs through the building envelope under the natural influences of wind and buoyancy pressures, or as a result of pressures produced by the operation of air handling systems. The airtig
17、htness characteristics of the building envelope obtained from the test can be used in the precise modeling of airflow through the building envelope. The following sections provide the explanations of various clauses in the standard. PREFACE This Commentary pertains to the CGSB standard CANKGSB-149.1
18、5-96, Determination of the Overall Envelope Airtightness of Buildings by the Fan Pressurization Method Using the Buildings Air Handling Systems.“ The main objectives of the Commentary are to provide details on the technical requirements and to offer explanation of various clauses and also to show fe
19、asible approaches for determining the air leakage characteristics of buildings. This standard can be applied to those buildings that have sufficient built-in air handling capacity. The air handling system can be either in supply or exhaust modes. The airtightness of the building envelope is determin
20、ed using the buildings installed air handling system. The air handling system is configured to create a pressure difference across the enclosed building envelope. The enclosed test volume can either be pressurized using the supply air systems or depressurized using the exhaust air systems. Readings
21、are taken of the airflow rate required to generate the necessary pressure difference across the envelope. A minimum of four sets of pressure and airflow readings is required to develop a correlation representing the airtightness of the building envelope. This procedure helps in determining the avera
22、ge air leakage rate of the enclosed envelope at a specified pressure difference. The buildings air handling system should be capable of pressurizing the interior zone(s) up to 60 Pa. However, for buildings incapable of obtaining 60 Pa, a minimum of 30 Pa is needed in order to obtain reasonable resul
23、ts. The capacity of the air handling system, either in supply or exhaust modes, should be at least in the range of 1.0 to 2.5 L/s per square meter of the building envelope considered in the test volume. For example, for a building with an envelope area of 12 O00 m, the capacity of the air handling s
24、ystem serving the test volume capacity should be about 30 O00 L/s. One of the principal requirements is to ensure that the test volume is sufficiently isolated from other non-test areas of the building and with a minimal amount of operational interference. it is our e.rperience thnr in most commerci
25、al buildings, especially office and industrial buildings, the air handling capacity is suficiently larger than what would be required for conducting the airtightness tests. The required capacity of air handling system can further be reduced to 0.7 to i .5 LIS per square meter of envelope area for bu
26、ildings thar are built afier I990 due to recent air barrier requirements. I CAN/CGSB-149.15-96 F3 Copyright Canadian General Standards Board Provided by IHS under license with CGSBNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-F4 Extract damper Outdoor air damper
27、(closed) (open) Supply fan (on) I A 1 Return fan Av/ 1 I (off) I Return damper (closed) Floor return Dampers (closed) Floor supply Dampers (open) Note: State of fanr and dampers during pressurization test conditions are shown in brackets. FIGURE F1 Schematic of Air Handling System Used for Pressuriz
28、ation Using Buildings Internai Fans This Commentary provides the brief background on the scope and objectives of airtightness testing of relatively large buildings. The procedure described in the standard is expected to give results within overly complicated mechanical systems; attached commercial a
29、reas (shopping floors); attachments to other buildings; and variations in floor plans and footprints. For example, where the underground parking facility extends to more than one building, the test building can be difficult to physically isolate for the test unless the garage can be isolated from th
30、e building. f. The flow measuring devices should be installed in the duct system according to good engineering practices4 as described in the standard. If it is not possible to ensure accuracy of flow measurements, the standard should not be used to determine the air leakage characteristics. For exa
31、mple, airflow measurements in large air distribution ducts (6 x 8 size) with not enough straight length may cause significant measurement inaccuracy and, in some cases, may be difficult to measure. 5 The standard is more suitable for buildings with mechanical rooms located at the top and/or at the b
32、asement level. If one of the mechanical floors is located at the mid-height of the building, it is twice as much work to seal or to isolate the test area. In these circumstances, the test should be devised to separately test the upper and lower portions from the mid-height mechanical floor. In some
33、buildings, it may not be practical to isolate the mid-height mechanical floors. F1.4.2 The following limitations relate to the interpretation of airtightness results: a. It should be also noted that the standard is based on the field investigations of several large buildings using dedicated air hand
34、ling systems. Systematic round robin testing has not been undertaken to establish and to prove the repeatability of airtightness test results. Therefore, the procedure described in the standard is expected to give results within b. Conducting the test; and C. Removing the test set-up and normalizing
35、 the systems. CAN/CGSB-149.15-96 F9 Copyright Canadian General Standards Board Provided by IHS under license with CGSBNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-F7.2. F7.2. t1 i F7.2 F7.2.1 F7.2.1.1 .2 .3 F7.2.1.4 F7.2.1.5 F7.2.1.6 STD-CGSB 147.L!i-Sb-CAN/CGSB
36、-FREN = 1874650 0033672 129 Planning and Preparation for the Test The planning and preparation for the airtightness test requires a significant amount of effort. During the planning stage, ensure the following aspects: Establish the scope and objectives for conducting the airtightness tests. a. What
37、 is the main purpose of the test? b. Is the test required to check construction quality or to identify envelope deficiencies? C. Is the test required to determine the airtightness of the whole building or a part of the building? d. What is the level of confidence that you expect in airtightness test
38、 results? e. If the test is conducted for identifying envelope deficiencies and air leakage paths, one should consider performing an infra-red thermographic investigation or other tools during the airtightness testing. Gather relevant information about the building. The par. 7.1.1 and 7.1.2 of the s
39、tandard elaborate on information gathering. Use the data sheets provided in Attachment A to gather details about the building and air handling systems. Survey the test area of the building thoroughly and establish a detailed plan for the test procedure. Make a detailed list of what needs to be seale
40、d, closed and other preparations. Sample data sheets are provided in Attachment A. Survey the air handling systems serving the test area and obtain the details required in the par. 7.1.2 of the standard, including the following: a. Establish airflow paths.for supply, return and exhaust systems servi
41、ng the test area. b. Based on the airflow paths, select an appropriate mode of operation of the system (supply or exhaust) which can be used with minimum disruptions to the existing systems. C. Evaluate the capacity of air handling fans and capabilities of flow controls. d. Determine the locations f
42、or airflow measurement stations according to good engineering practices. e. Take the necessary measurements for constructing the airflow and pressure measurement stations. The use of term “return air system” in the building should be understood properly. The return air system is the entire system fr
43、om the return air grilles, the return air ducts and fans, splitter which diverts portion of the return air through the “exhaust” or “relief“ dampers, and the remainder portion into the supply air system through the mixing or recirculation dampers. The recirculation duct or damper must be sealed off
44、during the pressurization or depressurization test procedures. Any fans located in the recirculation trunks of the system must be off, however, fans located in the return or exhaust trunks can be used for the depressurization test. Ceiling plenums are generally used for the return airflows in buildi
45、ngs. Evaluate the impact of pressurization or depressurization on the plenum. For on e.rampie. see chapter 14 of ASHRAE Handbook Fundamentais. 5 F10 CAN/CGSB-149-15-96 Copyright Canadian General Standards Board Provided by IHS under license with CGSBNot for ResaleNo reproduction or networking permit
46、ted without license from IHS-,-,-STD*CGSB 149-15-9b-CAN/CGSB-FREN II L874b50 0033b93 Ob5 M 71 F7:2.1.7 Based on the site surveys, prepare the following items: a. Construct necessary airflow measuring stations and calibrate according to the procedures described in the standard. b. Construct averaging
47、 total pressure tubes and static pressure taps and calibrate according to the procedure described in the standard. C. Construct necessary flow control devices. d. Build blockings, sealing planes and other isolation devices to seal the test section from the remainder of the building. e. Fabricate ave
48、raging pressure taps for measuring the average indoor and outdoor pressure differences. f. Select appropriate temperature and pressure measuring devices. F7.2.1.8 Inform and explain the various aspects of the testing to the field team members. It is recommended that specific functions be delegated t
49、o each team member. One person must lead and manage the overall team. The lead person ensures that each team member is familiar with the assignment. It is recommended that a mock test be carried out and all communication equipment be tested prior to the actual test. F7.2.1.9 Select tentative test dates for the airtightness test. It is recommended that two test dates be selected to allow for acceptable weather conditions. F7.2.1.1 O All intent
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