What is LPS 1181?

  • Est Time: 20 mins
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Tags: Fire Testing
Read our blog below and watch the video above to learn more about LPS 1181, don't forget to test you've understood everything by taking the short quiz afterwards.

LPS 1181 is an insurer approval reaction to fire test developed by the Loss Prevention Certification Board (LPCB) in consultation with the Association of British Insurers (ABI) and manufacturers. It examines and classifies the fire growth performance of built-up systems and insulated panels using the large scale ‘Garage Test’. 

How does the Garage Test work?

The test is carried out in a 10 m long, 4.5 m wide, 3 m high enclosure which is clad in the materials under examination.  The enclosure is open at the front (giving it the appearance of an open garage) and has a ventilation window to one side. A timber crib with a 1 MW fire load is placed in a rear corner. The crib is designed to burn for 20 minutes. 

The crib is ignited at the start of the test and fully extinguished after 30 minutes. The specimen is observed for a further 30 minutes after this point. 

The crib is ignited at the start of the test. After the crib has burnt out completely, the test is continued until all flaming of the panels, and in particular the insulation, has ceased completely. After 30 minutes it is permissible to extinguish any areas still flaming and cease recording. 

What is the difference between LPS 1181 Part 1 & 2?

The performance of external products is classified under LPS 1181 Part 1, whilst internal products are classified under part 2.

Part 1 – Tests cladding for external use

LPS 1181 Part 1 provides two main pass grades.

Grade EXT-B: A product that meets the requirements of LPS 1181:
•    no flashover at the ceiling; 
•    no sustained flaming outside the crib fire area; 
•    no external sustained flaming and / or fire penetration; 
•    no concealed burning; 
•    no fall of burning brands from the ceiling outside the crib area; and 
•    no part of the insulation core completely destroyed.   

Grade EXT-A: A product that meets the requirements of LPS 1181 and attains a minimum fire resistance of 30 minutes integrity and 15 minutes insulation under BS 476 part 21 and EN 1365 part 2 for roofs. 

This category is further sub-divided based on the results from LPS 1208 as shown below: 


Grade Integrity Insulation
EXT-A60 60 min 60 min*
EXT-A30 30 min 30 min*
EXT-A15 30 min 15 min

* Systems that achieve an insulation time within 90% of this figure can be deemed to pass.
Part 2 - Tests cladding for internal use

This provides three pass grades:
Grade Criteria
Int-3 Passes LPS 1181 in an internal configuration
Int-2 Passes LPS 1181 and 30 min fire integrity, 30 min insulation to fire resistance test BS476 part 22
Int-1 Passes LPS 1181 and 60 min fire integrity, 60 min insulation to fire resistance test BS 476 part 22

Post Test Assessment

LPCB carries out a number of post-test audits and tests to ensure the production quality of tested products is upheld.

Why is it a good indicator of real fire performance?

The scale and severity of the ‘garage test’ mean it can provide a more comprehensive assessment of the reaction to fire performance of a complete construction (including joints) when compared with the tests used in the Euroclass system