NF-7RS™ Safety Heads (Holders)

Pre-Torqued Safety Head

Performance Features

  • Insert type safety head that fits inside the bolt circle of companion flanges to allow for easy installation and removal
  • Pre-torqued capscrews clamp the rupture disk within the safety head, independently of companion flange bolts, which allows for future removal, inspection, and re-installation
  • A J-bolt ensures the safety head is fitted in the required direction between companion flanges by engaging a blind hole drilled on the inlet companion flange perimeter
  • Asymmetric alignment pins in the safety head mate with locating holes in the rupture disk, ensuring centering and correct orientation of the rupture disk within the safety head
  • Flow arrows on the side of the safety head indicate correct directional installation with process flow
  • Proprietary ‘bite seal’ on flat seating surface to optimize sealing between rupture disk and safety head process side allowing leak tightness of 10^-6cc/s He or greater
  • Can be equipped with pressure tapping in either inlet or outlet to allow installation of monitoring devices and sensors
  • For use with flanged piping connections; Raised face, Ring joint and tongue and groove flange facings. Designed for multi flange ratings and piping standards
  • The rupture disk dome fully protected within safety head inlet to avoid damage when installed into piping system
  • Available in Torque resistant version, specify NF-7RS-TR
  • Available as a double disk assembly

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  • Sizes & Pressures
  • Disks & Sensors
  • Materials & Option
  • Accessories
  • Documentation

Sizes & Pressures

NF-7RS™ Safety Head Dimensions

Disk Size Safety Head Flange Rating Overall Height Outside Dimensions Shape
in mm ANSI DIN JIS in mm in mm
1 25 150 6 - 1.5 38 2.6 67 square
300/600 10/16/25/40 10/16/20/30/40 1.5 38 2.9 73 square
1.5 40 150 - 10/16/20 1.7 43 3.4 86 square
300/600 10/16/25/40 30/40 1.7 43 3.7 95 square
2 50 150/300/600 10/16/25/40 10/16/20/30/40 1.9 48 4.1 104 square
3 80 150/300/600 10/16/25/40 10/16/20/40 2.2 55 5.2 133 square
- - 10 2.2 55 5.2 132 square
4 100 150/300 10/16/25/40 16/20/30/40 2.9 73 6.2 158 square
- - 10 2.9 73 6.2 158 square
600 - - 2.6 65 7.6 192 round
6 150 150/300 10/16/25/40 10/30/40 3.6 92 9.8 248 round
600 - - 4.5 114 10.4 264 round
8 200 150/300 - - 3.8 97 12.0 305 round
10 250 150/300 - - 4.3 110 14.1 359 round
12 300 150 - - 4.8 121 16.0 406 round
300 - - 5.3 133 16.5 419 round
14 350 150 - - 5.3 133 17.8 451 round
300 - - 5.9 149 19.6 483 round
16 400 150 - - 6.4 162 20.1 511 round
300 - - 7.1 181 21.1 536 round
18 450 150 - - 7.4 187 22.8 578 round
300 - - 7.9 200 23.4 594 round
20 500 150 - - 8.4 241 24.8 629 round
300 - - 8.6 219 25.6 651 round
24 600 150 - - 10.3 260 29.5 749 round
300 - - 10.8 273 30.4 772 round

Standard Materials

316 stainless steel and carbon steel.

Also available Monel® alloy 400, Inconel® alloy 600, Hastelloy® alloy C and C-276, aluminum, and titanium.

Torque Resistant Safety Head Option

The Type TR™ Series torque resistant safety head option offers the identical performance and flow characteristics valued from standard BS&B safety heads. The only difference – the TR Series Safety Heads are designed with a wider seating surface to be used with metal spiral wound gaskets at the flange. This distinct safety feature protects rupture disks from situations where plant personnel may overtorque rupture disks within piping systems.

Because of the wider seating surface of the TR Series Safety Head, the load is distributed over a much broader area reducing the influence of excessive torque transmitted to the disk.

Accessories

BS&B supplies many of the Accessories required to safely and conveniently install our overpressure relief devices and complementary products. Through our professional team and global network of sales engineers and procurement personnel, we are able to provide the highest quality accessory products to meet your installation requirements.

Saf-T-Change Quick Disk Replacement (QDR)

After activation, the replacement disk is quickly slid into place. Saving hours of lost production due to blown rupture disks.

Tell-Tale Assemblies & Excess Flow Valves/Gauges

A gauge tap in the outlet flange of the safety head may be considered when the safety head is installed in a vertical position.

Spare Safety Heads & Cap Screws

Jackscrews

When activated, the jackscrews effectively separate the flanges, providing adequate clearance to remove or insert a safety head and external gaskets.

Lifting Lug Eye Bolts

Eye bolts are recommended when weight and/or accessibility is a factor in lifting safety heads.

Baffle Plate

When a safety head is free-vented to atmosphere, a baffle plate may be considered to disperse overpressure and absorb recoil.

Product Literature

Nu-Saf™ Rupture Disk Brochure
Burst Alert Sensors Brochure

Installations

Nu-Saf™ Installation Instructions
Burst Alert Leak Dectector Installation Instruction
Burst Alert Sensor Installation Instruction