Tekanan Kerja Pipa ASTM A53 Seamless/Welded Sch 40

Mampukah Pipa ASTM A53 Gr. B Seamless Sch 40 diameter 2 Inch menahan tekanan uap sebesar 3 Bar yang umum diaplikasikan pada Pipa Steam Coil Storage Tank Minyak Sawit?

Atau, Mampukah Pipa ASTM A53 Gr. A Welded Sch 40 diameter 2 Inch menahan tekanan uap sebesar 3 Bar tersebut?

Jawabannya adalah sangat mampu.

Pertama, Sertifikat pabrikan menunjukan hasil "Good" pada uji Hydrotest tekanan 2300 psi atau setara dengan 159 BAR.
 

Kedua, hasil perhitungan dengan menggunakan persamaan Barlow adalah 2430 psi atau setara dengan 168 BAR.

Berikut ini adalah penjelasan tentang persamaan Barlow tersebut.

Maaf penjelasannya di bawah ini menggunakan bahasa Inggris. ini dilakukan untuk menghindari kesalahan translate pada variable-variable yang diketahui.

Working Pressure / Maximum Allowable Pressure

¹⁾ Working pressure is a term used to describe the maximum allowable pressure a pipe may be subjected to while in-service. Barlow's formula can be used to calculate the maximum allowable pressure by using design factors as:

^*1 psi (lb/in²) = 6,894.8 Pa (N/m²) = 6.895x10^-2 bar 

1.  ²⁾ Temperature derating factors  of steel pipes due to stress are indicated below:

Temperature		Temperature Derating Factor
(oF)	(oC)
< 250	< 121	1.00
250 - 300	121 - 149	0.97
300 - 350	149 - 177	0.93
350 - 400	177 - 204	0.90
400 - 450	204 - 233	0.87

2.  ¹⁾ The strength of a material is determined by the tension test which measure the tension force and the deformation of the test specimen.

a.      the stress which gives a permanent deformation of 0.2% is called the yield strength

b. The stress which gives rupture is called the ultimate strength or the tensile strength

Typical strength of some common materials:

Material	Yield Strength (psi)	Ultimate (Tensile) Strength (psi)
Stainless Steel, 304	30000	75000
6 Moly, S31254	45000	98000
Duplex, S31803	65000	90000
Nickel, N02200	15000	55000
A53 Seamless and Welded Standard Pipe, Grade A	30000	48000
A53 Seamless and Welded Standard Pipe, Grade B	35000	60000

3.  ³⁾ Longitudinal joint factor ( ) for steel Pipe

The longitudinal joint factor to be used in the design formula in § 192.105 is determined in accordance with the following table:

Specification	Pipe class	Longitudinal joint factor (E)
ASTM A 53/A53M	Seamless	1.00
	Electric resistance welded	1.00
	Furnace butt welded	.60
ASTM A 106	Seamless	1.00
ASTM A 333/A 333M	Seamless	1.00
	Electric resistance welded	1.00
ASTM A 381	Double submerged arc welded	1.00
ASTM A 671	Electric-fusion-welded	1.00
ASTM A 672	Electric-fusion-welded	1.00
ASTM A 691	Electric-fusion-welded	1.00
API Spec 5L	Seamless	1.00
	Electric resistance welded	1.00
	Electric flash welded	1.00
	Submerged arc welded	1.00
	Furnace butt welded	.60
Other	Pipe over 4 inches (102 millimeters)	.80
Other	Pipe 4 inches (102 millimeters) or less	.60

4.  ⁴⁾ Design factor ( ) for steel pipe.

(a) Except as otherwise provided in paragraphs (b), (c), and of this section, the design factor to be used in the design formula in § 192.105 is determined in accordance with the following table:

Class location	Design factor (F)
1	0.72
2	0.60
3	0.50
4	0.40

(b) A design factor of 0.60 or less must be used in the design formula in § 192.105 for steel pipe in Class 1 locations that:

(1) Crosses the right-of-way of an unimproved public road, without a casing;

(2) Crosses without a casing, or makes a parallel encroachment on, the right-of-way of either a hard surfaced road, a highway, a public street, or a railroad;

(3) Is supported by a vehicular, pedestrian, railroad, or pipeline bridge; or

(4) Is used in a fabricated assembly, (including separators, mainline valve assemblies, cross-connections, and river crossing headers) or is used within five pipe diameters in any direction from the last fitting of a fabricated assembly, other than a transition piece or an elbow used in place of a pipe bend which is not associated with a fabricated assembly.

(c) For Class 2 locations, a design factor of 0.50, or less, must be used in the design formula in § 192.105 for uncased steel pipe that crosses the right-of-way of a hard surfaced road, a highway, a public street, or a railroad.

(d) For Class 1 and Class 2 locations, a design factor of 0.50, or less, must be used in the design formula in § 192.105 for -

(1) Steel pipe in a compressor station, regulating station, or measuring station; and

(2) Steel pipe, including a pipe riser, on a platform located offshore or in inland navigable waters.

Reference:

1)    “Calculate pipes internal, allowable and bursting pressure”, November 9^th 2016, http://www.engineeringtoolbox.com/barlow-d_1003.html.

2)    “Temperature derating factor for steel pipes”, November 9^th 2016,http://www.engineeringtoolbox.com/temperature-derating-factor-steel-pipes-d_1744.html.

3)    “49 CFR 192.113 - Longitudinal joint factor (E) for steel pipe”, November 9^th 2016, https://www.law.cornell.edu/cfr/text/49/192.113.

“49 CFR 192.111 - Design factor ( F ) for steel pipe”, November 9^th 2016, https://www.law.cornell.edu/cfr/text/49/192.111.