frp flange design (part 2): asa150/300 flange

GPI Journal Vol. 2, No. 2

193

GPI Standards Committee

GPI7G-040 Published on Dec 27, 2016

Regular Article

Received on Aug 30, 2016.

Revised on Sep 27, 2016.

Accepted on Oct 11, 2016.

Featured Technology

FRP flange design (Part 2): ASA150/300 Flange

Yoshinori NISHINO1, Allen S CHIU2, Shinichi TAMURA1,

Masaki NISHINO1, Taiga TATSUMI1 1NBL Technovator Co., Ltd., 2NOV FGS Singapore (Pte) Ltd.

Abstract: In the first report, the design of optimal FRP flange was reported. In this second report, outcomes of

optimum ASA150/300 FRP flange design development to apply compression molding method for under 400mm,

and centrifugal molding method for more 400mm up to 3.5m are reported. Detailed research results are shown such

that the cost is about half of the conventional product and the quality is about 2 times.

Keywords: FRP flange, design, seal structure, centrifugal molding method, compression molding method, ASA150,

ASA300

1. Introduction

Features of the FRP flange, since a resin compressive strength

is weak compared to metallic materials, surface strength is

lower than the metal material, but since the reinforcing fiber is

light and the strength is higher than a metal material, in

disadvantages of metal

material. It has been

widely used in the

effective and high

pressure of the oil & gas

field [1] to certain

corrosion measures.

In this case, pick up

the ASA150 / 300

common flange standard

(flange size and bolt),

Contact mold flange of

the O-ring seal format

shown in Figure 1, which was carried out according to the new

design method in the first report [2] that it is an optimal detailed

product design result of up to the 3.5m diameter.

2. Design conditions of the product

Using a secondary processing is not required prepared by

centrifugal casting shown in Figure 1, it is reported in the

following detailed research results of the most rational Contact

mold flange subjected to effective design. (Patent pending

preparation)

Basic design model is shown in Figure 2. Design items

needed, ①standard compatible with the flange of the metal

material to be share, ② to maximize the quality performance

(endurance and the allowable pressure tolerance), to design a

product that can be ③ manufactured at a low cost (Minimum

material).

In other words, FRP flange that allows the ① ~ ③ are

shown in Figure 2, it is an adhesive bonding flange structure of

the same thinking such as weld type of metal flange, adopt a

structure in which the frictional force of adhesion employing

the scarf lap adhesive for the adhesive strength to the maximum

the bonding surface is maximized.

Flange thickness, obtains a necessary and sufficient value for

the tightening strength of the flange bolts by the stress

Ｆｉｇ 1 Ｃｏｎｔａｃｔ Flange

Fig.2 Strength of bonding flange3）4）

Ｆｉｇ 3 Ｓｔｒｅｎｇｔｈ of bonding Flange3)

Y. Nishino et al. / GPI Journal 2(2) (2016) 193-197

Global oil & gas Pipe Institute 194

calculation shown in Figure 3. In this paper, we propose a new

development in the GPI O-ring seal system, and a newly

developed groove type gland packing seal system furthermore.

Figure 4 (a) is an O-ring seal system of the backup ring junction

sandwiched between a conventional flanges. On the other hand,

Figure 4 (b), is a new development of O- ring seal system that

can be shared with metal flange, O- ring by two 1/2 diameter 0-

ring of the junction between the FRP · metal flange seal

becomes possible. In addition, the large-diameter O-ring seal of

the one in the FRP · FRP flange joint, it is possible to O- ring

seal. In O- ring to adapt to the ground packing flange or the like

with corresponding difficulty uneven structure was developed

groove-type gland packing seal system. Figure 4 (c) is a gland

packing seal system which covers the conventional flange

entire. In contrast, Figure 4 (d) is a new development groove

type gland packing seal system of providing a groove structure

groove for narrow gland packing only to the FRP flange side.

FRP · metal flange joint and is set to both allow the FRP ·

FRP flange joint. And structural calculation of FRP flange is

optimally designed with allowable stress calculation and use

material of a screw joint structure of GPI coupling similar 1/16

taper scarf wrap shown in Figure 2 [2]. Result of obtaining a

reasonable maximum efficiency, that the durability of the

packing material with minimum seat ring area is excellent in

stable sealing quality performance are the best, which is a new

O-ring system. Complementing it, it is more widely groove type

gland packing seal system that can be adapted to existing

equipment.

3. Flange bolts allowable load and the necessary

seal pressure (Influence of applied load of O-

ring and gland packing)

From the flange structure shown in Figure 2, the clamping

bolt force F, since the stress of the difference between the

sealing required force Fs becomes effective flange joining force,

basic quality performance flanges are determined by clamping

bolt standard flange shown in Figure 5 and the pipe diameter

The standard flange applications, maximum performance is

designed to take full advantage of the clamping force of the

provisions, it will be the compressive load of the seat ring

necessary to seal the minimum, that is, to minimize the seat ring

diameter. Figure 5 is at the optimum design seal structure of

each seal format shown in 500 to 1000mm diameter standard

flange data and 4 of the standard flange of ASA150 / 300,

standard bolt (yield point 200MPa) use, seal theory (the seat

ring 1.5 pressure) application, the axial force of the internal

pressure effect, is the calculation results of the moment the

maximum allowable breakdown voltage of the case of ignoring

the load from the piping structure. Green color in the figure is

assumed that the seat ring of the new O-ring system is in the

inner ring of the tube (new gland packing system is also the

same), gland packing system was calculated as necessary to 1.5

times the sealing pressure on the flange over the entire surface.

And shows the application bolt washer diameter and the ISO

standard bolt tightening torque necessary to stress the variance

for holding allowable compressive force of the weakness of the

FRP material the (200MPa or less) as a reference. In other

words, the tolerance of the durability of the AWWA technical

standards, since the required five times the safety factor of the

allowable stress, and to adopt a new O-ring system, ASA150 is

apply the internal pressure of the flange standard maximum

2MPa, SAS300 the maximum 3MPa. On the other hand, if you

adopt the gland packing, the ASA150, 300 both about 1MPa

and about 1.3MPa. In the short-term use of GPI standard (about

10 years), for the safety factor is 3 times, each new O-ring is

ASA150; 3MPa, ASA300; 5Mpa, gland packing in is ASA150;

1.6MPa, ASA300; 2MPa. The compression forces acting on

FRP flange using standard washer is about one-third the

allowable 200MPa the CS material ASA150 / 300 together

about 70MPa shown in Figure 5. On the other hand, the flange

bolts in the case of using high-tensile bolts, requiring changes

since the application of the use range of the allowable

compressive force of the FRP washers change or laminated

materials. Further, it applied load which is calculated by the

process piping design (thermal stress, etc. bending load) will

supplement that must be taken into account as well.

Fig.4 O-ring and grand packing of bonding flange5）８）

(a) Backup ring O-ring seal (b) New O-ring seal

(c) Grand packing seal (d) New groove grand packing seal


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Although it is possible to more FRP flange design that applies

a high pressure flange in the standard flange, here, it took up

ASA150, 300 general purpose.

4. New O-ring seal ASA150 / 300 flange

Figure 6 is a detailed design result of Contact mold flange

which adopted the new O-ring system of the standard flange of

ASA150 / 300. Left reference value standard flange of Figure 6

at (outer diameter, inner diameter, bolt hole and application

volts), followed by stress relieving the optimal balance detailed

structural dimensions designed structures, maximum

breakdown voltage of the standard bolt, the available acceptable

a breakdown voltage. Right figure is a detailed design result of

adaptation size and a groove of new O-ring. Left of right

diagram showing metal flange and the right is FRP flange. The

convex portion of the seat-Contact surface which is

characteristic of the metal flange ASA reference is constant

with 1.6 ㎜. However, R1 dimensions of the ASA flange and

JIS flange is different.

The dimensions of the recess R of FRP flange for all in

common, to adopt a dimension to add 4 mm in maximum

diameter to allow these. On the other hand, 0-installation of the

ring of the groove should be in the minimum diameter in order

to reduce the axial force. Single from the seal theory, double use

O-ring is to adopt a compression standard of the initial

deformation amount of 20%.ASA150 flange of the results

25mm ~ 3600 ㎜ is designed with four types of groove and

eight of the thickness of the O-ring. particular, most field 150

to 1500 ㎜ flange used is common d1: 6mm, d2: 12mm 2 types

of O-ring of and one kind of groove FRP flange w16mm, and

H5.6mm. The recess of the FRP flange corresponding to the

convex portion of the metal flange is as 1.6mm, can be shared

with the metal flange of purpose. It should be noted that, in class

150 (ASA150), even if the use of the general bolt adopted a new

O-ring seal, from one-third the allowable maximum value GPI

standard of 10-year durability is acceptable breakdown voltage

becomes 3MPa. In class 300 (ASA300) is the result of a 5MPa.

The compression force by bolts washers acting on the FRP

flange surface acts as shown in Figure 5. Further, since the acts

similarly like bending load, 10 years durability required for

these are necessary to design the strength borne as well.

5. Optimal design result of ASA150 · 300

The results of Figure 6, and can be shared between the

optimum product design purpose of the metal flange of

ASA150, 300, centrifugal casting production productivity with

the best performance (maximum allowable tolerance) at the

minimum material (material cost minimum) becomes the

maximum is a detailed results of the obtained optimum value

by the theoretical calculation simulation a capable product

design. Apply tube diameter that is another color at about 450

mm or less in the figure, compression molding method can take

higher productivity than the centrifugal casting production. The

material selection SMC is the best. In addition, until 1500 ㎜

of ASA150 flange thick part at the optimal material is 7 mm CS

is optimal strengthening 25 mm CS glass fiber. Its content is

optimal selection of about thin 50 wt% ~ about 60 wt% thick.

In the above 1500 mm, WR (roving Cross: suitable, such as

one-way weave) and the sharing of a decrease of more

reinforcement material.

Furthermore, when ND 450 mm or less, 25 mm short fiber

material including about 30% filler is used for SMC material.

For 500-1500 mm, 50 ~ 60% wt of CS is used for centrifugal

casting 7 ~ 25 mm CS. A large flange of 1800 mm or more is

designed by composite laminate in which WR is laminated on

the surface layer. Note that the application resins, to decrease

material cost, to decrease curing time to about at least less than

one hour is required, even the curing time of epoxy resin is

slower than 20 minutes, shortest polyester resin. Therefore,

product manufacturing costs, the results are vinyl ester resins

specifications as compared to the epoxy resin used is low.

Looking at product weight, material cost of the object, it

Ｆｉｇ５ Allowable Pressure of ASA150/300 Flange by Bolt

Y. Nishino et al. / GPI Journal 2(2) (2016) 193-197

Global oil & gas Pipe Institute 196

had

to

have

on

average halved as compared with the existing Vanstone flange

(40%) Prototype result of the check, the product performance

as designed is obtained.

Incidentally, the flange assembly, seal ring reamer pin

specification for the centering and the adhesive by the caulking

material in the flange was needed. Further, details will be

t

Ｆｉｇ６ FRP Design forASA150/300 Flange by New ０-ring system2）６）７）８）


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omitted, in the above applications 1MPa must be used as shown

in Figure 6 standard plastic back-up ring in addition to the O-

ring seal.

And, check production rate of 600 mm prototype, it takes

time to casting from material supply is about 10 minutes, curing

demolding was required about 30 minutes. To confirm the

production of a total of 40 minutes / book. It was confirmed that

it is still secondary processing production of unnecessary

casting products. .

6. Conclusion

Structure of optimum flange to adhesive bonding in the first

Report, reported the research results, such as approximate

calculation methods such as design basic sheet ring seal and

material selection and allowable stress. Contact mold flanges

employing the new O-ring system is reported conclusion that

the optimum basic structure flange.

Based on the conclusion, optimal design results of the

theoretical calculation simulation of Contact mold flange Part 2

is to be adhesively bonded adopted the new O-ring seal of the

general-purpose standard flange such as the ASA flange and

JIS16K of class 150 and 300 (3500 ㎜ up) was reported.

The obtained research results of the research goals, but may

be ① a common junction ② necessary material half, also

half the production cost, ③ product design of optimal flange

that product quality is twice was obtained.

It should be noted that the results of this research is to append

that it is a pending patent application preparation.

References

[1] Allen S. Chiu, Performance Requirements of FRP

Tubular for Oil& Gas Production, Japan Reinforced

Plastics, Vol.33, No. 3, pp. 97-103 (1987).

[2] Yoshinori Nishino, Allen. S. Chiu, Shinichi Tamura,

Masaki Nishino, Taiga Tatsumi, FRP flange design (Part

1) Necessary strength and optimum structure, GPI

Jounal, Vol.2, No.2, pp.187-192 (2016).

[3] Masaki Uhara, Taiga Tatsumi, Masaki Nishino, Shinichi

Tamura, Yoshinori Nishino, Study on the production of

the flange by the centrifugal forming method (Part 1),

GPI Journal Vol. 1, No. 2, pp. 262-267 (2015).

[4] Masaki Uhara, Taiga Tatsumi, Masaki Nishino,

Shinichi Tamura, Yoshinori Nishino, Study on the

production of the flange by the centrifugal forming

method (Part 2), GPI Journal Vol. 1, No. 2, pp. 268-273

(2015).

[5] Yoshinori Nishino, Merits of and design method for

long-distance FRP piping, The Piping Engineering,

H10‐01A．Vol. 30, No. 5．131-138 (1988).

[6] Takashi Shimosakon, Masaki Uhara, Taiga Tatsumi,

Shinichi Tamura, Yoshinori Nishino, Design Method of

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[7] Takashi Shimosakon, Shinichi Tamura, Yoshinori

Nishino，GPI standard Corrosion FRP High Pressure

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[8] Yoshinori Nishino, Construction method of secondary

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ⓒVSP1991.

frp flange design (part 2): asa150/300 flange

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