1、NSF International Standard / American National StandardNSF/ANSI 240 - 2017Drainfield Trench Product Sizing forGravity Dispersal Onsite WastewaterTreatment and Dispersal SystemsNSF International, an independent, not-for-profit, non-governmental organization, is dedicated to being the leading global p
2、rovider of public health and safety-based risk management solutions while serving the interests of all stakeholders. This Standard is subject to revision. Contact NSF to confirm this revision is current. Users of this Standard may request clarifications and interpretations, or propose revisions by c
3、ontacting: Chair, Joint Committee on Wastewater Technology c/o NSF International 789 North Dixboro Road, P.O. Box 130140 Ann Arbor, Michigan 48113-0140 USA Phone: (734) 769-8010 Telex: 753215 NSF INTL FAX: (734) 769-0109 E-mail: infonsf.org Web: http:/www.nsf.org i NSF International Standard/ Americ
4、an National Standard for Wastewater Treatment Systems Drainfield Trench Product Sizing for Gravity Dispersal Onsite Wastewater Treatment and Dispersal Systems Standard Developer NSF International NSF International Board of Directors Designated as an ANSI Standard January 21, 2017 American National S
5、tandards Institute NSF/ANSI 240 2017 ii Prepared by The NSF Joint Committee on Wastewater Technology Recommended for Adoption by The NSF Council of Public Health Consultants Adopted by NSF International November 2011 Revised February 2017 Published by NSF International PO Box 130140, Ann Arbor, Mich
6、igan 48113-0140, USA For ordering copies or for making inquiries with regard to this Standard, please reference the designation “NSF/ANSI 240 2017”. Copyright 2017 NSF International Previous editions 2011 Unless otherwise specified, no part of this publication may be reproduced or utilized in any fo
7、rm or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from NSF International. Printed in the United States of America. iii Disclaimers1 NSF, in performing its functions in accordance with its objectives, does not assume or undertake to disc
8、harge any responsibility of the manufacturer or any other party. The opinions and findings of NSF represent its professional judgment. NSF shall not be responsible to anyone for the use of or reliance upon this Standard by anyone. NSF shall not incur any obligation or liability for damages, includin
9、g consequential damages, arising out of or in connection with the use, interpretation of, or reliance upon this Standard. NSF Standards provide basic criteria to promote sanitation and protection of the public health. Provisions for mechanical and electrical safety have not been included in this Sta
10、ndard because governmental agencies or other national standards-setting organizations provide safety requirements. Participation in NSF Standards development activities by regulatory agency representatives (federal, local, state) shall not constitute their agencys endorsement of NSF or any of its St
11、andards. Preference is given to the use of performance criteria measurable by examination or testing in NSF Standards development when such performance criteria may reasonably be used in lieu of design, materials, or construction criteria. The illustrations, if provided, are intended to assist in un
12、derstanding their adjacent standard requirements. However, the illustrations may not include all requirements for a specific product or unit, nor do they show the only method of fabricating such arrangements. Such partial drawings shall not be used to justify improper or incomplete design and constr
13、uction. Unless otherwise referenced, the annexes are not considered an integral part of NSF Standards. The annexes are provided as general guidelines to the manufacturer, regulatory agency, user, or certifying organization. 1 The information contained in this Disclaimer is not part of this American
14、National Standard (ANS) and has not been processed in accordance with ANSIs requirements for an ANS. Therefore, this Disclaimer may contain material that has not been subjected to public review or a consensus process. In addition, it does not contain requirements necessary for conformance to the Sta
15、ndard. iv This page is intentionally left blank.v Contents 1 General . 1 1.1 Purpose 1 1.2 Scope . 1 1.3 Alternate materials, design, and construction 1 1.4 Classification of related products . 2 1.5 Product literature 2 1.6 Design and construction. 2 1.7 Sample Collection 2 2 Normative references .
16、 3 3 Definitions . 3 4 Long term acceptance rate (LTAR) evaluation . 6 4.1 Sizing relationships for related products 6 4.2 Study limitations . 6 4.3 Performance testing and evaluation 6 5 Field performance assessment (FPA) 14 5.1 Study conditions and limitations . 14 5.2 FPA study type weighting. 15
17、 5.3 Data quality attributes and values 15 5.4 Expert panel (EP) appointments 18 5.5 Development of individual FPA scoring methodology and endpoint score 18 5.6 Minimum endpoint score required to claim conformance 19 5.7 Final report . 19 Annex A . A1 vi This page is intentionally left blank.vii For
18、eword2 This American National Standard, NSF/ANSI 240 Drainfield Trench Product Sizing for Gravity Dispersal Onsite Wastewater Treatment and Dispersal Systems Standard, has been developed as part of the ongoing efforts of interested parties to establish minimum material, design, construction, and per
19、formance requirements for comparing gravity dispersal drainfield products based on hydraulic performance used in place of conventional coarse aggregate within onsite wastewater treatment and dispersal systems. This Standard also specifies the minimum literature that manufacturers shall supply to aut
20、horized representatives. Two alternate methods for establishing the sizing relationship are provided: (1) The Long Term Acceptance Rate (LTAR) establishes a methodology for determining the drainfield sizing relationship between gravity fed natural coarse aggregate and alternative manufactured produc
21、ts by measuring their relative long term acceptance rates (LTAR). The evaluation shall be conducted at an approved testing organization where independent variables are suitably controlled. Bottom area sizing and infiltration rate comparisons are based on test center data collected using multiple pro
22、duct and control trench cells under accelerated hydraulic loading conditions. (2) The Field Performance Assessment (FPA) methodology evaluates relative failure rate studies of systems constructed using alternatives to conventional natural coarse aggregate. This methodology compares drainfields botto
23、m area (footprint) with respect to the systems hydraulic performance (hydraulic failure) to arrive at a suitable bottom area relationship. Technologies in use for 10 or more years may apply for certification under this option. The comparative treatment performance of alternative products compared to
24、 performance of conventional systems is not within the scope of this Standard. Issue 2 NSF/ANSI 240 was originally published in 2011. As part of the NSF standards maintenance process, it is due for its 5-year reaffirmation. No changes have been made to the standard. This Standard was developed by th
25、e NSF Joint Committee on Wastewater Technology using the consensus process described in the American National Standards Institute. Suggestions for improvements of this Standard are welcome. This Standard is maintained on a Continuous Maintenance schedule and can be opened for comment at any time. Co
26、mments should be sent to Chair, Joint Committee on Wastewater Technology, c/o NSF International, Standards Department, PO Box 130140, Ann Arbor, Michigan 48113-0140, USA. 2 The information contained in this Foreword is not part of this American National Standard (ANS) and has not been processed in a
27、ccordance with ANSIs requirements for an ANS. Therefore, this Foreword may contain material that has not been subjected to public review or a consensus process. In addition, it does not contain requirements neces-sary for conformance to the Standard. This page is intentionally left blank.1 2017 NSF
28、NSF/ANSI 240 2017 NSF International Standard for Wastewater Treatment Systems Drainfield Trench Product Sizing for Gravity Dispersal Onsite Wastewater Treatment and Dispersal Systems 1 General 1.1 Purpose The purpose of this Standard is to establish minimum material, design, construction, and perfor
29、mance requirements for comparing gravity dispersal drainfield products based on hydraulic performance used in place of conventional coarse aggregate within onsite wastewater treatment and dispersal systems. This Standard also specifies the minimum literature that manufacturers shall supply to author
30、ized representatives. Two alternate protocols for establishing the sizing relationship are provided. 1.1.1 Long term acceptance rate (LTAR) In 4, the long term acceptance rate (LTAR) of gravity dispersal drainfield products using alternatives is compared to conventional coarse aggregate trench media
31、. Bottom area sizing and infiltration rate comparisons are based on test center data collected using multiple product and control trench cells under accelerated hydraulic loading conditions. Independent variables that may affect hydraulic infiltration shall be controlled. 1.1.2 Field performance ass
32、essment (FPA) Field Performance Assessment (FPA) methodology evaluates relative failure rate studies of systems constructed using alternatives to conventional natural coarse aggregate. This methodology compares drainfields bottom area (footprint) with respect to the systems hydraulic performance (hy
33、draulic failure) to arrive at a suitable bottom area relationship. Manufacturers of general use products, as defined in 3, which include technologies in use for 10 or more years, may apply for certification under this Standard, including a statement of the bottom area relationship. 1.2 Scope This St
34、andard provides a methodology to compare, assess and document product sizing criteria for alternative or proprietary products with respect to conventional coarse aggregate used in onsite wastewater dispersal drainfields, based on comparative hydraulic performance. The comparative treatment performan
35、ce of alternative products compared to performance of conventional systems is not within the scope of this Standard. 1.3 Alternate materials, design, and construction While specific materials, designs, and constructions may be stipulated in this Standard, products that incorporate alternate material
36、s, designs, or constructions may be acceptable when it is verified that such products meet the applicable requirements. NSF 2017 NSF/ANSI 240 2017 2 1.4 Classification of related products Drainfield products within a manufacturers family of products are classified according to the performance testin
37、g and evaluation of a representative model within the series. 1.5 Product literature 1.5.1 Installation information Manufacturers shall provide comprehensive and detailed installation instructions to authorized representatives. The manual shall be written to be easily understood by the intended read
38、er and shall include, at a minimum: design, construction, and material specifications for the products components; off-loading and unpacking instructions including safety considerations, identification of fragile components and measures to be taken to avoid damage to the product; clear description o
39、f product installation requirements, including plumbing requirements, miscellaneous fittings and appurtenances; installation considerations, if any, based on site soils and slope; for products with sharp surfaces, provide safe handling instructions; step by step installation procedures for the produ
40、ct; repair or replacement instructions in the event that a product possesses flaws that would inhibit proper functioning; and list of sources where replacement components shall be obtained. 1.5.2 Manufacturer documentation The manufacturer shall prepare and maintain documentation for each product, i
41、ncluding: model number; basic description of the product; complete drawings of the product; safe handling and installation instructions; design basis data essential for proper operation under differing field conditions; and comprehensive and detailed discussion of product fundamentals. 1.6 Design an
42、d construction 1.6.1 Structural integrity The product manufacturer shall provide documentation that the product it proposes to certify shall withstand a 16,000 pound axle load under 12 in (0.31 m) of cover showing no evidence of collapsing, fracturing, or breaking. 1.7 Sample collection All sample c
43、ollection and laboratory analytical methods shall be in accordance with Standard Methods3 unless otherwise specified. NSF 2017 NSF/ANSI 240 2017 3 2 Normative references The following documents contain provisions that, through reference in this text, constitute provisions of this Standard. At the ti
44、me of publication, the indicated editions were valid. All Standards are subject to revision, and parties are encouraged to investigate the possibility of applying the most recent edition of the Standards indicated below. American Public Health Association (APHA), American Water Works Association (AW
45、WA) expressed mathematically as D60/D10. 3.30 verification agency: The organization responsible for oversight of the testing organization in preparation and completion of LTAR testing and FPA review, and in preparation, review and completion of the final report. 4 Long term acceptance rate (LTAR) ev
46、aluation The purpose of this section is to establish a drainfield sizing relationship between gravity fed natural coarse aggregate and alternative manufactured products by measuring their relative long term acceptance rates (LTAR). The evaluation shall be conducted at an approved testing organizatio
47、n where independent variables are suitably controlled. 4.1 Sizing relationships for related products There is a sizing relationship between the product and control determined in 4 or 5 of this Standard that may be applied to all other models within the same family of products, so long as they are pr
48、oportionately equivalent. The width and length of the design may vary provided that the product width is 1 ft (0.31 m) or 4 ft (1.22 m). 1. For odd number of products in the family of products, the median product width shall be tested; or 2. For even number of products in the family of products, the
49、 tested product shall be at least as wide as the mid-point of the range of widths within the family of products. 4.2 Study limitations This Standard yields a direct comparison of product performance with respect to a control under accelerated test conditions. The unit of measure for comparison is the LTAR (GPD/ft2). This Standard is not intended to assess the performance of a pump or pressure distribution system. This Standard does not establish product longevity. 4.3 Performance testing and evaluation 4.3.1 Test preparation and
