Reinforcing Pad Or RePAD Or RF Pad Pipe Branch 90°And 45° 8''X8''

Reinforcing Pad or RePAD or RF Pad Pipe branch 90°and 45° 2'' 3'' 4'' 6'' 8'' 10''

 

What is a Reinforcement PAD?

 

Reinforcing Pad or RePAD or RF Pad (Fig. 1) is a donut-shaped pad that goes around the branch of a branch

joint to add strength to the joint. It resembles a round metal washer that has been bent to conform to the curvature

of the pipe.

 

With the increase in pipe size, the cost of branch connection fittings increases. Sometimes, such fittings are not readily

available as standard pieces. So, it is a standard method to fabricate the tee by cutting a hole in the header and welding

the branch in the pipe. But the section where the straight pipe is punctured becomes weak section due to the presence of

that hole. So to handle the pressure and reduce the stress concentration in that region the thickness is increased locally

in the form of reinforcement pad or RF Pad. Similar situation arises for Pressure Vessel Nozzle Connections. To increase

the pressure and load carrying capability of the equipment nozzles, RF Pad are welded. These reinforcement pads provides

additional strength and capability to the pipe.

 

Material	Carbon steel, stainless steel, alloy steel, duplex stainless, nickel alloy steel
Carbon steel	ASTM A234 WPB, WPC;
Stainless steel	304/SUS304/UNS S30400/1.4301 304L/UNS S30403/1.4306; 304H/UNS S30409/1.4948; 309S/UNS S30908/1.4833 309H/UNS S30909; 310S/UNS S31008/1.4845; 310H/UNS S31009; 316/UNS S31600/1.4401; 316Ti/UNS S31635/1.4571; 316H/UNS S31609/1.4436; 316L/UNS S31603/1.4404; 316LN/UNS S31653; 317/UNS S31700; 317L/UNS S31703/1.4438; 321/UNS S32100/1.4541; 321H/UNS S32109; 347/UNS S34700/1.4550; 347H/UNS S34709/1.4912; 348/UNS S34800;
Alloy steel	ASTM A234 ,WP1,WP12 CL1,WP12 CL2,WP11 CL1,WP11 CL2,WP11 CL3,WP22 CL1,WP22 CL3,WP24,WP5 CL1,WP5 CL3,WP9 CL1,WP9 CL3,WPR,WP91,WP911,WP92,; ASTM A860 WPHY42/WPHY52/WPHY60/WPHY65; ASTM A420 WPL3/WPL6/WPL9;
Duplex steel	ASTM A182 F51/S31803/1.4462; ASTM A182 F53/S2507/S32750/1.4401; ASTM A182 F55/S32760/1.4501/Zeron 100; 2205/F60/S32205; ASTM A182 F44/S31254/254SMO/1.4547; 17-4PH/S17400/1.4542/SUS630/AISI630; F904L/NO8904/1.4539; 725LN/310MoLN/S31050/1.4466 253MA/S30815/1.4835;
Nickel alloy steel	Alloy 200/Nickel 200/NO2200/2.4066/ASTM B366 WPN; Alloy 201/Nickel 201/NO2201/2.4068/ASTM B366 WPNL; Alloy 400/Monel 400/NO4400/NS111/2.4360/ASTM B366 WPNC; Alloy K-500/Monel K-500/NO5500/2.475; Alloy 600/Inconel 600/NO6600/NS333/2.4816; Alloy 601/Inconel 601/NO6001/2.4851; Alloy 625/Inconel 625/NO6625/NS336/2.4856; Alloy 718/Inconel 718/NO7718/GH169/GH4169/2.4668; Alloy 800/Incoloy 800/NO8800/1.4876; Alloy 800H/Incoloy 800H/NO8810/1.4958; Alloy 800HT/Incoloy 800HT/NO8811/1.4959; Alloy 825/Incoloy 825/NO8825/2.4858/NS142; Alloy 925/Incoloy 925/NO9925; Hastelloy C/Alloy C/NO6003/2.4869/NS333; Alloy C-276/Hastelloy C-276/N10276/2.4819; Alloy C-4/Hastelloy C-4/NO6455/NS335/2.4610; Alloy C-22/Hastelloy C-22/NO6022/2.4602; Alloy C-2000/Hastelloy C-2000/NO6200/2.4675; Alloy B/Hastelloy B/NS321/N10001; Alloy B-2/Hastelloy B-2/N10665/NS322/2.4617; Alloy B-3/Hastelloy B-3/N10675/2.4600; Alloy X/Hastelloy X/NO6002/2.4665; Alloy G-30/Hastelloy G-30/NO6030/2.4603; Alloy X-750/Inconel X-750/NO7750/GH145/2.4669; Alloy 20/Carpenter 20Cb3/NO8020/NS312/2.4660; Alloy 31/NO8031/1.4562; Alloy 901/NO9901/1.4898; Incoloy 25-6Mo/NO8926/1.4529/Incoloy 926/Alloy 926; Inconel 783/UNS R30783; NAS 254NM/NO8367; Monel 30C Nimonic 80A/Nickel Alloy 80a/UNS N07080/NA20/2.4631/2.4952 Nimonic 263/NO7263 Nimonic 90/UNS NO7090; Incoloy 907/GH907; Nitronic 60/Alloy 218/UNS S21800
Package	Wooden cases, pallets, nylon bags or according to the customers' requirements
MOQ	1pcs
Delivery time	10-100 days depending on quantity
Payment terms	T/T or Western Union or LC
Shipment	FOB Tianjin/Shanghai, CFR, CIF, etc
Application	Petroleum/Power/Chemical/Construction/Gas/Metallurgy/Shipbuilding etc
Remarks	Other materials and drawings are available.
Welcome to contact us.

 

Why is the reinforcement pad required?

 

RePADs or RF Pads are plates used to reinforce components and/or nozzles by increasing thickness local to the component

in high stressed zones. These are made from the same size and material as the pipe header to which they are welded.

On pipes or Pressure vessels, holes are made in the form of nozzle or branch intersection and thus the parent pipe/ vessel

is weakened and high-stress zones created. Hence, It is obvious to compensate for this weakness with a Reinforcing Pad to

reduce the possibility of failure, as it strengthens the piping branch connection or the pressure vessel nozzle.

 

Uses of Reinforcing PAD

 

1. Normally Reinforcing pads are used at stub-on and stub-in branch connections if required per the line list or if required

per the branch chart in the piping material specification. By using reinforcing pads it is not required to strengthen the complete

header pipe. Clause 304.3.3 of ASME B 31.3 provides equations to check if any welded piping branch connection requires

reinforcement.

 

2. Support trunnions are provided with reinforcement when specified by piping stress engineers. When supports loads of trunnions

are more than the bearing capability of the trunnion, reinforcing pads are welded at the parent pipe and trunnion junction to enhance

it's load-carrying capability. However please keep in mind that reinforcement on trunnions from elbows is not suggested as standard

practice, So it should be avoided to the maximum extent possible. The requirement of reinforcement must be specifically mentioned

in the isometric drawing for conveying to the construction team.

 

3. Equipment nozzle connections are normally reinforced so that nozzles can carry more loads and moments from the piping side.

 

4. Sometimes, Reinforcing pads are provided in-between shoe or saddle support and parent pipe when parent pipe thickness is less

than required.

 

Fig. 1: Typical Reinforcing PADs

 

Design Features of RF PAD

 

Normally Maximum thickness that is used in engineering companies as reinforcing pad thickness is 1.5 times parent pipe thickness.

Standard practice is to use the same thickness as the parent pipe.

The reinforcement material must be compatible with the parent and branch pipe material. Normally same material as the header pipe

is used as RF Pad.

 

Clause 328.5.4.g of ASME B31.3 mentions that Reinforcing pads and saddles shall have a good fit with the parts to which they are

attached.

 

A vent hole shall be provided at the side (not at the crotch) of any pad or saddle to reveal leakage in the weld between the branch

and run and to allow venting during welding and heat treatment. Normally 2 numbers of vent holes are provided which must be sealed

with mastic or silicone gel to restrict the water flow inside the RF Pad. Vent holes are also known as weep holes or Telltale holes. The

normal size of the weep hole is 6 mm. If the reinforcement pad is made of multiple pipe cuts, than a vent hole should be provided in

each cut piece.

A pad or saddle may be made in more than one piece if joints between pieces have strength equivalent to pad or saddle parent metal,

and if each piece has a vent hole.

 

Reinforcing pad symbol in Drawings

 

Fig. 2 shows the normal RF Pad symbol that is used in piping drawings.

 

Fig. 2: Reinforcing PAD symbol

 

The reinforcing pad is a ring cut from a steel plate that has a hole in the center equal to the outside diameter of the branch connection.

It is slipped onto the branch pipe before the branch pipe is welded to the header. Once the branch has been welded to the header, the

reinforcing pad is slid down the branch to cover the weld connection. The reinforcing pad is than welded to both the branch and the

header.