Security Rated Door SR4

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Strongdor Securidor plus

Securidor+ S4 security door range is accredited to offer a high level of security against potential attacks from heavy duty tools such as felling axes and disc grinders. These single and double door sets are available in a wide range of bespoke sizes, with over 100 locking options and a choice of RAL/ BS colours. The range is suited for use in high-security installations, such as the Ministry of Defence, banks, schools, utility buildings, sub-stations and Home Office approved gun rooms. Bespoke security-rated steel door-sets. LPS1175: Level 4 Issue 8 Cert/LPCB ref. 1542c

  • Secure for sure with Strongdor
  • 129 locking systems available
  • Compatible with access controls
Unique Range Features

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Easy fit doors
1 year warranty

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Made in Britain Colour

Product Features

Height Icon

Single - up to 2.75m
Double - up to 2.75m

Width Icon

Single - up to 1.284m
Double - up to 2.492m

Strongdor Icons Acoustic
Acoustic Rating

Est 35 dB

Thermal Transmittance

U Value Est. 2.28

Further information


The welded frame is made from reinforced 1.5mm steel and a 38mm x 100mm single rebated profile, reinforced at the hinges, lock keeps and fixing points.

Manufactured from 1.5mm steel on the inner and outer face, the composite door leaf is 45mm thick with an integral astragal lip to the closing edge. It weighs approximately 80kg per square metre.

Standard threshold
Leading face fits under the door - see below

Certified by the Loss Prevention Certification Board to LPS 1175 Level 4 Issue 8 Cert/LPCB Ref. 1542c

Key Features
The range is certified to LPS1175 level 4, and fitted with extreme heavy duty hinges complete with 2 integral dog bolts per hinge. Constructed to resist attack from high powered cordless tools, felling axes, disk grinders, jigsaws etc.

Wide choice of finishes available including powder-coated finish from our range of RAL or BS colours.

Choice of personnel, panic and escape hardware, with over 100 locking options available - including single and multi-point bolting. All escape hardware complies with BS EN 179. A full list of compliant hardware can be found at

Optional Extras
Certified Louvres available up to 400mm square.

Standard Threshold

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Security Rated Leaf and Frame

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Securidor4 TechSpec Thumbnail 22

Securidor+ Level 4

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Strongdor Standard Colours 22 Thumbnail

Standard Colours & Coatings

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SR4 Steel door fitting instructions

SR4 Security Fitting Guide

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Door Configurations

Door Configurations for Steel Doors with security rating 3 & 4

Sr3 Doubles
Sr3 Singles

Over 150 colours available

View Colour Options

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