三木　悟2012.12.25 maksgym

Trivia about Important Points for Manufacturing of Pipe （ 配 管 製

作 の 注 意 事 項 ）

No.

Description

1 小口径（１００Ａ以下）の配管に対して内外面に塗装を施す場合は、直管で最大２０００ｍｍ、曲管を含む場合は最大１０００ｍｍまでとしないと内面塗装が出来ない。塗装流し込み作業になると塗装面積単価から工賃単価になってしまうので、小口径配管でも価格がＵＰする。

Length of Small Size Pipe viewed from painting work

When the painting is applied to internal surface and external surface of small size pipe which is less than DN100, the length of pipe shall be restricted to be as follows in order to enable the painting of the internal surface:1) In case of straight pipe

: max. Length 2000mm2) In case of pipe which contains bend

: max. Length 1000mm

When painting of internal surface is carried out by paint pouring method, cost for painting for small size pipe is increased because painting cost is changed from unit price per area to unit price per wage.

2 上記のような配管条件長さにならない場合は、フランジ継ぎ手を増やす方がトータル価格も安くなる。ボルト・ナット・パッキンが増えるが、現場での合わせる作業がやりやすくなる。搬入・移動もやりやすくなる。

When the length of each pipe exceeds the above condition , the total cost of pipes will be cheaper by increasing the number of flange connections.Although the total quantities of bolts, nuts and gaskets will be increased, the assembling work at the site will be easier.In addition, carrying in and transportation of the pipes will be easier.

3 どうしても１の条件にならない場合は、亜鉛メッキすると安くなる。外面の仕上げ色は、亜鉛メッキに上塗りして色合わせをする方法ができる。

When the conditions shown in the above Item 1 are not satisfied due to some reasons, it will be cheaper way to change painting to galvanizing.As to color matching of the surface, there is a method that applies the specified finishing color to the galvanized external surface.

4 小口径の配管では、管割寸法及び形状を塗装しやすいことを優先させて考えること。（ＳＳ配管）

＊２００３．６．１７　アロイテック　山田殿からのご指導

As to small pipes, the lengths of pipes and the shapes of pipes shall be determined by considering first the easiness of painting.

* Advice given by pipe manufacturer named Alloy-tech on 11/6/2003.

5 特 殊 フランジ（ Ｉ Ｓ Ｏ ） は、 国 内 で In Japanese market, special flange such as the

Trivia about Important Points for Manufacturing of Pipe （配管製作の注意事項） 1

は市 販 性 なし。 鋼 板 材 から削 りだしするので、 納 期 ・ コストに注 意 すること。例）７Ａ－６６０４ ヨルダン／ザルカ

flange for ISO is not available as standard goods.Note delivery time and cost of special flange because it is made by machining of steel plate.

Trivia about Important Points for Manufacturing of Pipe （配管製作の注意事項） 2

6 鋼 板 厚 みには” ±” の製 品 公 差 があるので、 Ｓ Ｐ Ｅ Ｃ ． に記 載 がない場合には客先に確認を取ること。７ Ａ － ６ ０ ２ ９ 　 ベトナム／ ドンナイにてＳ Ｐ Ｅ Ｃ ． に鋼 管 厚 みについて ” Minimum Wall Thickness” と 記載 されていたことに対 して、 ” － ”公差分を考慮せず製作仕様書で ” No minus tolerance” に て 提 出 し て し まった。現 場 製 品 確 認 検 査 時 に管 厚 みをチェックされて、 管 厚 がＳ Ｐ Ｅ Ｃ ． の数値 より薄 い厚 みであることが発 覚 して不 良 品 扱 いとなった。 （ 各 種 規 格<JIS,AWWA,ASTM,ISO> の 公 差 を 引用）　　＊鋼管に限らずいろいろな材料には製作公差があるので注意すること。

Tolerance for Thickness of Steel Plate and Wall Thickness of Pipe

1. There are tolerances of ± for thickness of steel plate and wall thickness of fabricated steel pipe that are manufactured in accordance with international standard.

2. On the other hand, “Minimum Wall Thickness” for each nominal diameter of steel pipe is specified in Technical Specification for project of “7A-6026 Dong Nai / Vietnam”.Some of the above “Minimum Wall Thicknesses” are equal to “Nominal Wall Thicknesses” of SPG of JIS.

3. However, manufacturing specification for steel pipes has been submitted for Consultant’s approval by describing that “No minus tolerances” are applied to the wall thicknesses of pipes without noticing the contradiction between the above Item 1 and Item 2.In spite of the above fact, the person in charge of design forgot to describe sentence that “No minus tolerances are allowed for wall thicknesses of pipes” in the manufacturing drawings of pipes.Therefore, the important criteria has not been informed to the manufacturer’s of pipes.

4. At the time of inspection of completed pipes by Consultant and Employer, the wall thicknesses of pipes were measured and:1) Some of wall thicknesses of pipes were

thinner than “Minimum Wall Thickness”, although those were within the minus tolerance for thickness of steel plate specified in JIS.

2) Consultant and Employer insisted that “ Minimum Wall Thickness ” described in project Technical Specification does not

allow “ minus tolerance ” .3) From the above, the pipes, which were

thinner than “Minimum Wall Thickness”, were judged as rejected products.

Trivia about Important Points for Manufacturing of Pipe （配管製作の注意事項） 3

7 亜 鉛 メ ッ キ 鋼 管 (SGPW) に つ い て 、水 道 用 亜 鉛 メッキ鋼 管 （ ダブルメッキ）は製造中止となっています。市販されている亜鉛メッキ鋼管は、シングルメッキとなっており、４ｍ長さが製品基準長さで、５ . ５ｍ長さは特殊製品になる。

Galvanized Steel Pipe (SGPW in JIS)

The manufacturing of galvanized steel pipe, which is galvanized two times (double galvanized), has already been stopped.

The commercially available galvanized steel is: - Single galvanized steel pipe (= steel pipe

which is galvanized one time only)- Standard length is 4 m- Length of 5.5 m is special product

Trivia about Important Points for Manufacturing of Pipe （配管製作の注意事項） 4