NSF ANSI 40:2018 pdf free download – Residential wastewater treatment systems
1.2 Scope
This Standard contains minimum requirements for residential wastewater treatment systems having rated treatment capacities between 1514 Liday (400 gal/day) and 5678 L/day (1500 gal/day). Management methods for the treated effluent discharged from residential wastewater treatment systems are not addressed by this Standard. System components covered under other NSF or NSF/ANSI standards or criteria shall also comply with the requirements therein. This Standard shall in no way restrict new system designs, provided such designs meet the minimum specifications described herein.
1.3 Alternate materials, design, and construction
While specific materials, designs, and constructions may be stipulated in this Standard, systems that incorporate alternate materials, designs, or constructions may be acceptable when it is verified that such systems meet the applicable requirements.
1.4 Performance classification
For the purpose of this Standard, systems are classified according to the chemical, biological, and physical characteristics of their effluents as determined by the performance testing and evaluations described herein. All systems within a manufacturer’s model series may be classified according to the performance testing and evaluation of the system with the smallest hydraulic capacity within the series. Performance testing and evaluation of larger systems within the series (having hydraulic treatment capacities within the scope of this Standard) may not be necessary provided that the dimensions, hydraulics, mixing and filtering capabilties, and other applicable design characteristics are proportionately equivalent to the evaluated system.
2 Normative references
The following documents contain provisions that, through reference in this text, constitute provisions of this Standard. At the time of publication, the indicated editions were valid. All standards are subject to revision, and parties are encouraged to investigate the possibility of applying the recent editions of the standards indicated below.
4 Materials
Materials shall be durable and capable of withstanding stresses and wear during shipping, assembly, installation, and operation. System materials shall not be adversely affected when subjected to the use environment. NOTE – Because there are numerous design criteria suitable for the manufacture of residential wastewater treatment systems, manufacturers should acquire appropriate engineering expertise in evaluating the design of the system. Interior surfaces The interior surfaces of the system shall be free of spalls, honeycombs, and pits with the exception that rough surfaces, intended to support microbiological growth, shall be permitted. Interior surfaces shall show no visible signs of structural change following performance testing and evaluation including, but not limited to, flaking, pitting, or the formation of structurally significant cracks.
4.2 Exterior surfaces
Exterior surfaces shall show no visible signs of structural change fllowing performance testing and evaluation including, but not limited to, flaking, piting, or the formation of structurally significant cracks. NOTE一Small surface cracks exhibited by concrete tanks are normally expected in some circumstances and shall not be considered structural deterioration.
4.3 Welding
Welded seams and deposited weld material shall meet the requirements of Sections 4.1 and 4.2. Welds and welding methods shall conform to ANSI/AWS D1.14 for steel 1/8 in (3.2 mm) and thicker or ANSI/AWS D1.34 for steel that is less that 1/8 in (3.2 mm). The welds shall be visually inspected and shall be acceptable if the criteria of Table 6.1 of ANSI/AWS D1.14 are satisfied. The location, type and size of welds shall be shown on the drawings required in Section 9. Welds that do not conform to the manufacturer ‘s drawings, based on visual examination of the weld, shall be repaired prior to testing and the repairs noted in the final report. The system shall be free from cracks at the interface between the base metal and the weld, or within the weld metal.