An advisory in the Foreword (I.C. "Acceptance") addresses the certification of products which will be used in contact with potable water in accordance with ANSI/NSF 61. State and local jurisdictions may already require product certification and identification. Most industry manufacturers, including all NAPF members, routinely apply this certification to each product intended for potable water use.
Also enclosed are some examples of specifications for your consideration. These suggestions incorporate some of the revision's general issues but also address some options you may care to include.
Should you have questions or comments regarding this standard please let us know. This is a document in evolution and our association would be pleased to consider, and perhaps represent, all viewpoints which contribute to its forward progress.
REVIEW OF STANDARD
BASIC - Simply referencing the new standard (ANSI/AWWA C115/A21.15) assures conformity to the following major elements and standards:
Minimum class 53 DIP per ANSI/AWWA C151/A21.51
Flange dimensions per ANSI B16.1
All fabrication provisions
Asphaltic exterior coating per ANSI/AWWA C151/A21.51
"Ductile iron pipe in interior locations shall be provided with flanged joints conforming to ANSI/AWWA C151/A21.15"
IMPORTANT - Although much optional material is included in this standard (Foreword p.x) and is discussed in the following paragraphs, the standard requires specifiers to select the interior pipe lining. For general service the Foreword recommends (lll.A.3.a) cement mortar linings over asphaltic linings, although both are referenced within the Standard proper (Sec.4.4.2 and 4.4.3)
"Flanged pipe shall be furnished with cement mortar lining in accordance with ANSI/AWWA C104/A21.4"
ADVISORY - The Foreword (I.C. Acceptance") contains an advisory directing specifiers to the state or local agency having jurisdiction over potable water additive requirements (i.e. ANSI/NSF 61) to identify certification requirements for all products which contact potable water. Thus far approximately 30 states have adopted ANSI/NSF 61 as their standard for compliance. Most industry manufacturers, and all NAPF members, are certified by accredited third party organizations to this standard. By requirement, each product carries evidence of certification(i.e.label, stamp, stencil, etc.)
"Manufacturer or fabricator shall furnish independent 3rd party evidence of compliance with ANSI/NSF 61 for each piece of pipe which contacts potable water"
OPTIONS: The standard includes certain options (summarized in Foreword p.x) which, if desired, must be included in the material specifications. The following are arranged per that summary:
1. Certification - specifiers may, at their option, require a sworn statement form the manufacturer or fabricator that the flanged pipe complies with the requirements of this standard. Specifiers may also choose to require third party certification by accredited organizations. NAPF requires this certification for all it's members.
"Manufacturer or fabricator shall provide evidence of compliance to the provisions of ANSI/AWWA C115/A21.15 by an accredited third party organization such as Underwriters Laboratories (UL) or an approved equal"
2. Inspection (Sec. 5.2.1) - Purchaser may desire to personally inspect the manufacture's or fabricator's plant.
"Manufacturer and/or fabricator shall provide access to its facility for the inspection of flanged pipe"
3. Flange Material (Sec. 4.2.3) - Specifiers may choose to select material used for flanges. Both gray iron and ductile iron flanges meet the requirements of the standard and either may be used unless specified otherwise.
"All flanges shall be ductile iron"
4. Flanges (Sec. 4.2.1) - Specifiers may choose to select from optional flange types (Table-2 Solid or Table-3 Hollowback). Both types meet the requirements of this standard and either may be used unless otherwise specified.
"Flanges shall Table-2 Solid Type" or "Flanges shall be Table-3 Hollowback type" Note: Table-3 flanges are ductile iron only.
5. Bolt hole Alignment (Sec. 4.3.3) - Specifiers may desire alignment or tolerance values to meet unusual conditions which are not described in the standard.
6. Outside Coating (Sec. 4.4.1) - Specifiers may desire to specify coating other than asphaltic.
"Exterior surfaces of flanged pipe shall be provided with a shop applied primer compatible with the coating system specified in contract documents"
7. Special Coatings and Linings (Sec. 4.4.5) - Specifiers may require the use of special coating and lining products to meet particular service requirements.
"Flanged pipe for air lines shall be unlined"
8. Pipe Wall Thickness (Table 1) - Under certain conditions, specifiers may require ductile pipe wall thickness greater than minimum Class 53 shown on Table 1.
9. Bolt Holes Tapped for Studs (Sec. 4.2.4) - Specifiers may desire flanges with bolt holes tapped for studs bolts (i.e. wall pipes with flanges embedded in concrete) as shown in Table 2 and 3.
"Wall pipe flanges embedded in concrete shall be brilled and tapped for stud bolts per the tables"
National Association of Pipe Fabricators Recommended Flanged Pipe Specification "Flanged Ductile iron pipe shall conform to the provisions of ANSI/AWWA C115/A21.15-94 or the latest revision thereof. Pipe shall be furnished with cement mortar lining in accordance with ANSI/AWWA C104/A21.4 and the interior coating and lining shall also comply with ANSI/NSF 61 "Drinking Water System Componants-Health Effects "for all piping which contacts potable water."
ALSO... "Evidence of compliance with ANSI/AWWA C115/A21.15 and ANSI/NSF 61 shall be provided by an accredited third party such as Underwriters Laboratories (UL) or approved equal"
OPTIONS TO SPECIFICATION
"Flanges shall be ductile iron".
"Exterior surfaces of flanged pipe shall be provided with shop primer compatible with the coating system specified in the contract documents."
"Wall pipe flanges embedded in concrete shall be drilled and tapped for stud bolts per the tables."
本文转自：China Industry News