CAN CGSB-149 12-2017 Radon mitigation options for existing low-rise residential buildings.pdf

1、CAN/CGSB-149.12-2017National Standard of CanadaCanadian General Standards BoardRadon mitigation options for existing low-rise residential buildingsThe CANADIAN GENERAL STANDARDS BOARD (CGSB), under whose auspices this standard has been developed, is a government agency within Public Services and Pro

2、curement Canada. CGSB is engaged in the production of voluntary standards in a wide range of subject areas through the media of standards committees and the consensus process. The standards committees are composed of representatives of relevant interests including producers, consumers and other user

3、s, retailers, governments, educational institutions, technical, professional and trade societies, and research and testing organizations. Any given standard is developed on the consensus of views expressed by such representatives.CGSB has been accredited by the Standards Council of Canada as a natio

4、nal standards-development organization. The standards that it develops and offers as National Standards of Canada conform to the criteria and procedures established for this purpose by the Standards Council of Canada. In addition to standards it publishes as National Standards of Canada, CGSB produc

5、es standards to meet particular needs, in response to requests from a variety of sources in both the public and private sectors. Both CGSB standards and CGSB national standards are developed in conformance with the policies described in the CGSB Policy and Procedures Manual for the Development and M

6、aintenance of Standards.CGSB standards are subject to review and revision to ensure that they keep abreast of technological progress. CGSB will initiate the review of this standard within five years of the date of publication. Suggestions for their improvement, which are always welcome, should be br

7、ought to the notice of the standards committees concerned. Changes to standards are issued either as separate amendment sheets or in new editions of standards.An up-to-date listing of CGSB standards, including details on latest issues and amendments, and ordering instructions, is found in the CGSB C

8、atalogue at our Web site www.tpsgc-pwgsc.gc.ca/ongc-cgsb/index-eng.html along with more information about CGSB products and services.Although the intended primary application of this standard is stated in its Scope, it is important to note that it remains the responsibility of the users of the stand

9、ard to judge its suitability for their particular purpose.The testing and evaluation of a product against this standard may require the use of materials and/or equipment that could be hazardous. This document does not purport to address all the safety aspects associated with its use. Anyone using th

10、is standard has the responsibility to consult the appropriate authorities and to establish appropriate health and safety practices in conjunction with any applicable regulatory requirements prior to its use. CGSB neither assumes nor accepts any responsibility for any injury or damage that may occur

11、during or as the result of tests, wherever performed.Attention is drawn to the possibility that some of the elements of this Canadian standard may be the subject of patent rights. CGSB shall not be held responsible for identifying any or all such patent rights. Users of this standard are expressly a

12、dvised that determination of the validity of any such patent rights is entirely their own responsibility.LanguageIn this Standard, “shall” states a mandatory requirement, “should” expresses a recommendation and “may” is used to express an option or that which is permissible within the limits of this

13、 Standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their app

14、lication.Further information on CGSB and its services and standards may be obtained from:The Manager Standards Division Canadian General Standards Board Gatineau, Canada K1A 1G6A National Standard of Canada is a standard developed by an SCC- accredited Standards Development Organization (SDO), and a

15、pproved by the Standards Council of Canada (SCC), in accordance with SCCs: Requirements and Guidance-Accreditation for Standards Development Organizations, and Requirements and Guidance-Approval of National Standards of Canada Designation. More information on National Standard requirements can be fo

16、und at www.scc.ca. An SCC-approved standard reflects the consensus of a number of experts whose collective interests provide, to the greatest practicable extent, a balance of representation of affected stakeholders. National Standards of Canada are intended to make a significant and timely contribut

17、ion to the Canadian interest. SCC is a Crown corporation within the portfolio of Industry Canada. With the goal of enhancing Canadas economic competitiveness and social well-being, SCC leads and facilitates the development and use of national and international standards. SCC also coordinates Canadia

18、n participation in standards development, and identifies strategies to advance Canadian standardization efforts. Accreditation services are provided by SCC to various customers, including product certifiers, testing laboratories, and standards development organizations. A list of SCC programs and ac

19、credited bodies is publicly available at www.scc.ca. Users should always obtain the latest edition of a National Standard of Canada from the standards development organization responsible for its publication, as these documents are subject to periodic review.The responsibility for approving standard

20、s as NSCs rests with:Standards Council of Canada 55 Metcalfe Street, Suite 600 Ottawa, Ontario K1P 6L5, CANADAby telephone 819-956-0425 or 1-800-665-2472by fax 819-956-5740by mail CGSB Sales Centre Gatineau, Canada K1A 1G6in person Place du Portage Phase III, 6B1 11 Laurier Street Gatineau, Quebecby

21、 email ncr.cgsb-ongctpsgc-pwgsc.gc.caon the Web www.tpsgc-pwgsc.gc.ca/ongc-cgsb/index-eng.htmlHow to order Publications:Published November 2017 by the Canadian General Standards Board Gatineau, Canada K1A 1G6 HER MAJESTY THE QUEEN IN RIGHT OF CANADA, as represented by the Minister of Public Services

22、 and Procurement, the Minister responsible for the Canadian General Standards Board (2017).No part of this publication may be reproduced in any form without the prior permission of the publisher.Radon mitigation options for existing low-rise residential buildingsCETTE NORME NATIONALE DU CANADA EST D

23、ISPONIBLE EN VERSIONS FRANAISE ET ANGLAISE.ICS 91.120.99NATIONAL STANDARD OF CANADA CAN/CGSB-149.12-2017CAN/CGSB-149.12-2017 CGSB 2017 All rights reservedCANADIAN GENERAL STANDARDS BOARDCommittee on Radon Mitigation(Voting membership at date of approval)Chair (Voting)Whyte, J. Health Canada (General

24、 interest)General interest categoryBilal, M. Heating, Refrigerating and Air Conditioning Institute of CanadaBrossard, M. Health CanadaCryer, S. Pinchin Environmental Ltd.Krstic, G. Fraser Health AuthorityLafontaine, M. Physics Solutions Inc.Von Schoenberg, P. Public Services and Procurement CanadaWo

25、od, B. CARSTProducer categoryDalgleish, L. National Air Barrier AssociationForest, D. Venmar Ventilation Inc.Gelinas, P. Duchesne 2. the length and intensity of the cumulative exposure of an individual (to indoor radon) in the buildings where they spend most of their time.NOTE There are other lung c

26、ancer risk factors such as socio-economic, behavioral, occupational, biological and environmental. The combined effects of radon exposure and smoking tobacco can significantly increase the risk of lung cancer. Although the exposure to radon gas indoors and in occupational settings has been associate

27、d with an increased risk of developing lung cancer, there is not sufficient evidence in the published literature for the association with other diseases1. Due to a difference in air pressure between the inside of a building and the soil surrounding the foundation, soil gases, including radon may ent

28、er through openings in the foundation such as construction joints, gaps around service pipes and support posts, floor drains and sumps, cracks in foundation walls and in floor slabs, and openings in concrete block walls. Mitigation of existing homes with high levels of radioactive radon gas is a com

29、plex task, associated with many variables. It is recommended that radon mitigation be performed by a knowledgeable, specially trained radon mitigator such as a Canadian National Radon Proficiency Program (C-NRPP) certified radon mitigator.Radon is soluble in water and affects well water sources rath

30、er than surface waters which are more commonly used for municipal water supplies. When large volumes of water are used for domestic purposes, the radon dissolved in the water outgasses into the air. The health risk associated with radon dissolved in water is not from drinking the water, but from bre

31、athing the air into which the radon gas has been released. Potential entry routes for radon are illustrated in Figure 1.1 You can consult the World Health Organization (WHO) Radon handbook, September 2009 viewed 2017-07-13. Available from CAN/CGSB-149.12-2017iii CGSB 2017 All rights reservedNOTE 1 T

32、he only way to know if a home has a high radon concentration is to measure the radon concentration.NOTE 2 Figure has been taken from Health Canada, Radon Reduction Guide for Canadians, May 2014.Figure 1 Potential entry points of radon in foundation walls and poured concrete floorsIn 2007 the Governm

33、ent of Canada in conjunction with the Federal Provincial Territorial Radiation Protection Committee updated its guideline for exposure to radon in indoor air after a broad public consultation process which was based on new scientific information on health risk from indoor radon exposure.The current

34、Government of Canada Guideline for radon in indoor air is: Remedial measures should be undertaken in a dwelling whenever the average annual radon concentration exceeds 200 becquerels per cubic metre (Bq/m) in the normal occupancy area. The higher the radon concentration, the sooner remedial measures

35、 should be undertaken. When remedial action is taken, the radon level should be reduced to a value as low as practicable. The construction of new dwellings should employ techniques that will minimize radon entry and will facilitate post-construction radon removal should this subsequently prove neces

36、sary.For more information about radon and the Guideline, visit the Health Canada website https:/www.canada.ca/en/health-canada/services/environmental-workplace-health/radiation/radon.html#wb-info or call 1-800-O-Canada.4Potential entry routes for radon in homes with poured concrete foundations inclu

37、de cracks, areas with exposed soil or rocks, openings for utility fixtures or hollow objects such as support posts (see figure 1).Figure 1 nullypical radon entry routes in poured concrete foundation walls and nullors.in crawl spacesCracks or flaws infoundation wallsHollow objects such as supportpost

38、sAround utility penetrationsand support postFloor/wall jointsCracks or flaws in floor slabExposed soil or rock Floor drains the radon concentration in the soil gas; the building foundation design and construction; the pressure differences between the building and the soil.In addition to short-term v

39、ariations in indoor radon concentrations around the monthly average radon value, the monthly average itself varies from season to season, with the highest values usually occurring during winter months. Because of these variations, a measurement duration of at least three months during the heating se

40、ason will generally provide a conservative estimate of the annual average. If the result of the long-term measurement is greater than 200 Bq/m (5.4 pCi/L), Health Canada recommends that remedial action be undertaken. A short-term measurement of two to seven days is only acceptable as a rapid indicat

41、ion of radon concentration, for example, as an initial check on the success of a mitigation system installation. As it may not represent the actual long term average radon concentration, short-term testing should always be followed up with a long term test. The results of a short-term radon test sho

42、uld never be used to assess the need for radon mitigation in a house. While the health risk from radon exposure below the Canadian guideline decreases as the concentration is reduced, no level can be considered risk free. It is the choice of each homeowner to decide what level of radon exposure they

43、 are willing to accept. The mitigation method chosen is influenced by the initial radon concentration test results, the degree of radon reduction desired by the homeowner, the building type, and the costs associated with the method. How the basement or foundation area is used by a homeowner can affe

44、ct their expectations of the installation appearance and the cost. Mitigation of high levels of radon gas in a home may be accomplished using two basic methods. Either high levels of radon are kept from entering the building, or the radon which has already entered the home is diluted with outdoor ai

45、r. An established method of keeping radon from entering a building is active soil depressurization (ASD). ASD systems utilize a fan to create a negative pressure on the soil side relative to the interior of the building and thus exhaust the radon-laden soil gas to the outdoors where it is rapidly di

46、luted. Typical radon reductions associated with different mitigation techniques are presented in Annex A.The effectiveness of ASD in combination with sealing soil gas entry routes for radon control has been extensively proven, and the system typically does not significantly increase building energy

47、usage when it is well-designed and operated, therefore ASD should always be the first choice for reducing radon levels. ASD systems require little maintenance, function well for many years with an average fan life expectancy up to ten years, and typically reduce radon levels from 50 to 99%. Occasion

48、al replacement of the fan ensures the functionality of the system far into the future. The family of ASD systems consist of several different methods depending on the building construction.CAN/CGSB-149.12-2017v CGSB 2017 All rights reservedBuildings that have a fully poured concrete floor slab use s

49、ub-slab depressurization (SSD) and buildings that have exposed soil or other native materials use sub-membrane depressurization (SMD). Sump depressurization (SD), drain tile depressurization as well as block-wall depressurization are variants on soil depressurization where a depressurization fan is connected to a sump pit, drain tile network, or cavities of a block wall structure respectively to reduce radon levels. In SSD systems, the mitigation contractor cores through the existing concrete floor and connects to the gas permeable layer.