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Associate

Join Date: Jun 2014
Location: India
Posts: 26

# B16.5 Flange Thickness Deviation

11/18/2017 1:48 AM

Hi All,

Is there any possibilities to accept the flange thickness which is deviated from standard ASME B16.5 ? else anything has mentioned in the standard itself to accept the deviation... i have read, but i couldn't found anything like that...

if not, Do we have any alternate calculation to accept the same???

FYI, 0.5mm flange thickness has been deviated from the standard....

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Guru

Join Date: Jan 2010
Location: Mineral wells Tx
Posts: 616
#1

### Re: B16.5 Flange Thickness Deviation

11/18/2017 5:11 AM

ASME B16.5 - 2009 POINT 6 DIMENSIONS

6.1.1 Minimum Wall Thickness. For inspection purposes,

the minimumwall thickness, tm, of flanged fittings

at the time of manufacture shall be as shown in Tables 9

and 12 (Tables II-9 and II-12 of Mandatory Appendix II),

except as provided in para. 6.1.2. The additional metal

thickness needed to withstand installation bolt-up

assembly stresses, shapes other than circular, and stress

concentrations must be determined by the manufacturer,

since these factors vary widely. In particular, 45-deg

laterals, true Ys, and crosses may require additional reinforcement

to compensate for inherent weaknesses in.................

7.4 Flange Thickness

Required tolerances for flange thickness are as follows:

Size Tolerance

NPS ≤ 18 +3.0, −0.0 mm (+0.12, −0.0 in.)

NPS ≥ 20 +5.0, −0.0 mm (+0.19, −0.0 in.)

NPS ≤ 10 +1.0, −0.0 mm (+0.03, −0.0 in.)

NPS ≥ 12 +1.5, −0.0 mm (+ 0.06, −0.0 in.)

Associate

Join Date: Jun 2014
Location: India
Posts: 26
#2

### Re: B16.5 Flange Thickness Deviation

11/18/2017 5:52 AM

Whitephone; Thanks for the reply. the dimensions was undersized in the lower limit... there is no tolerance limit in the negative end.. is the right thing if we have used flange fittings clauses for valve flanges???? Please guide me....

Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 20005
#3

### Re: B16.5 Flange Thickness Deviation

11/18/2017 8:26 AM

It must be certified by the manufacturer for intended use....

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Guru

Join Date: Jan 2010
Location: Mineral wells Tx
Posts: 616
#4

### Re: B16.5 Flange Thickness Deviation

11/18/2017 10:03 AM

Yes, The criteria is similar

ASME B16. 47 (Large diameters)

7.2 Flange Thickness

Required tolerances for flange thickness, tf, are as

follows:

Flange Thickness, tf Tolerances

tf ≤ 25 mm (1.0 in.) +3.0 mm, −0.0 mm

(+0.12 in., −0.00 in.)

25 mm (1.0 in.) < tf ≤ 50 mm (2.0 in.) +5.0 mm, −0.0 mm

(+0.19 in., −0.00 in.)

50 mm (2.0 in.) < tf ≤ 75 mm (3.0 in.) +8.0 mm, −0.0 mm

(+0.31 in., −0.00 in.)

tf > 75 mm (3.0 in.) +10.0 mm, −0.0 mm

(+0.38 in., −0.00 in.)

AND

B16.5 (NPS 1/2 Through NPS 24)

Required tolerances for flange thickness are as follows:

Size Tolerance

NPS ≤ 18 +3.0, −0.0 mm (+0.12, −0.0 in.)

NPS ≥ 20 +5.0, −0.0 mm (+0.19, −0.0 in.)

NPS ≤ 10 +1.0, −0.0 mm (+0.03, −0.0 in.)

NPS ≥ 12 +1.5, −0.0 mm (+ 0.06, −0.0 in.)

I suggest you to take a look in these standards.

Guru

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting ["brexit" - ugh] as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 27042
#5

### Re: B16.5 Flange Thickness Deviation

11/19/2017 12:21 PM

It's all about risk. In deviating from the standard, the risk transfers from the insurers that expect compliance to the standard, to the deviant.

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Guru

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting ["brexit" - ugh] as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 27042
#6

### Re: B16.5 Flange Thickness Deviation

11/20/2017 8:24 AM

This is the domain of the Loss Adjuster. The role of this occupation is to adjust the insurance company's loss downwards.

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Join Date: Mar 2011
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Posts: 14345
#7

### Re: B16.5 Flange Thickness Deviation

11/20/2017 9:40 AM

NO. You cannot slide around the standards just by asking.

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