1、NSF International Standard / American National StandardNSF/ANSI 240 - 2011Drainfield 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 November 29, 2011 American National
5、Standards Institute NSF/ANSI 240 2011 ii Prepared by The NSF Joint Committee on Wastewater Technology Recommended for Adoption by The NSF Council of Public Health Consultants Adopted by The NSF Board of Directors November 2011 Published by NSF International PO Box 130140, Ann Arbor, Michigan 48113-0
6、140, USA For ordering copies or for making inquiries with regard to this Standard, please reference the designation “NSF/ANSI 240 2011.” Copyright 2011 NSF International Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or m
7、echanical, including photocopying and microfilm, without permission in writing from NSF International. Printed in the United States of America. iii Disclaimers1NSF, in performing its functions in accordance with its objectives, does not assume or undertake to dis-charge any responsibility of the man
8、ufacturer 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, including con-sequential damages, arising o
9、ut 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 Standard because governmental agencie
10、s or other national standards-setting organizations provide safety requirements. Participation in NSF Standards development activities by regulatory agency representatives (federal, lo-cal, state) shall not constitute their agencys endorsement of NSF or any of its Standards. Preference is given to t
11、he use of performance criteria measurable by examination or testing in NSF Stan-dards 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 understanding their adjacent stand
12、ard 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 im-proper or incomplete design and construction. Unless otherwise refere
13、nced, the annexes are not considered an integral part of NSF Standards. The an-nexes are provided as general guidelines to the manufacturer, regulatory agency, user, or certifying or-ganization. 1The information contained in this Disclaimer is not part of this American National Standard (ANS) and ha
14、s 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 neces-sary for conformance to the Standard. iv This page is intent
15、ionally 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 . 3 3 Definitions . 3 4 Long t
16、erm 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 5.3 Data quality attributes a
17、nd 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 Foreword2 This American National
18、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 ongo-ing efforts of interested parties to establish minimum material, design, construction, and performance re-quirements for co
19、mparing 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 authorized representa-tives. Tw
20、o 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 manu-factured products by measuring their rela
21、tive 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 col-lected using multiple product and control trench c
22、ells under accelerated hydraulic loading condi-tions. (2) The Field Performance Assessment (FPA) methodology evaluates relative failure rate studies of systems constructed using alternatives to conventional natural coarse aggregate. This metho-dology compares drainfields bottom area (footprint) with
23、 respect to the systems hydraulic per-formance (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 performance of conven
24、tional systems is not within the scope of this Standard. This Standard was developed by the NSF Joint Committee on Wastewater Technology using the consen-sus process described in the American National Standards Institute. Suggestions for improvements of this Standard are welcome. Comments should be
25、sent to Chair, Joint Committee on Wastewater Technology, c/o NSF International, Standards Department, PO Box 130140, Ann Arbor, Michigan 48113-0140, USA. 2The information contained in this Foreword is not part of this American National Standard (ANS) and has not been processed in accordance with ANS
26、Is 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 2011 NSF NSF/ANSI 240 2011
27、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 performance requirements
28、 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 authorized representativ
29、es. 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. Bottom area sizi
30、ng 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 assessment (FPA) Fiel
31、d 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 (hydraulic failure) t
32、o 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 Standard provides a
33、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 performance of alternative
34、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 materials, designs, or con
35、structions may be acceptable when it is verified that such products meet the applicable requirements. NSF 2011 NSF/ANSI 240 2011 2 1.4 Classification of related products Drainfield products within a manufacturers family of products are classified according to the performance testing and evaluation o
36、f 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 reader and shall inclu
37、de, 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 of product installa
38、tion 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 product; repair or repl
39、acement 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, including: model nu
40、mber; 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 and construction 1.6
41、.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 collection and labo
42、ratory analytical methods shall be in accordance with Standard Methods3 unless otherwise specified. NSF 2011 NSF/ANSI 240 2011 3 2 Normative references The following documents contain provisions that, through reference in this text, constitute provisions of this Standard. At the time of publication,
43、 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 (AWWA) expressed math
44、ematically 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) evaluation The purpo
45、se 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 organization where independen
46、t 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 proportionately equi
47、valent. 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 tested product sh
48、all 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).
49、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 product evaluation The control and manufactured products shall be evaluated in identical test cells within a standardized soil matrix. The products and controls hydraulic infiltration performance shall be compared using wastewater containing identical constituent concentrations. The control and test products shall be
