Understanding IK Ratings and Their Relevance to Lighting

The Purpose of IK Ratings

IK Rating (Impact Protection) is an international standard unit for classifying electrical enclosures, including lighting, and the force of impact that they can endure. Outlined by the IEC (International Electrotechnical Commission) regarding electrical enclosures in general in IEC 62262:2002 – and mirrored by BS EN 62262, with further clarification specifically for luminaires (lighting) in IEC TR 62696:2011, this creates a standardised framework to indicate how impact-resistant light fittings are.

The IK rating comes from testing with a blunt object at increasingly higher energy impacts. This test is typically conducted by using a weighted object (hammer) and gravity to apply the force in an easily measurable and repeatable manner. The techniques for this are outlined in detail further on, but are stipulated in the EN/IEC 60068-2-75 (BS EN60068-2-75) standard.

Relevance to Light Years Ahead

Because of the sensitive nature of many of the key markets that Light Years Ahead specialises in; namely custodial lighting and mental healthcare lighting, the light fittings must be impact-resistant to a suitable level depending on where they are situated.

Of particular importance to custodial and mental healthcare is the avoidance of potential for the creation of a ligature point, should the luminaire be subject to vandalism or deliberate abuse. Other welfare-based reasons include mitigating the chance of making an improvised weapon from any broken parts. From an operational perspective a more robust light fitting will reduce downtime, by keeping as many areas fully-functional and as safe as possible.

Light Years Ahead applies this expertise to designing and manufacturing luminaires for other environments and industries where robust IK Ratings are equally important. These include transport lighting and industrial lighting applications, where IK-rated lights are important due to the potential for accidental damage or vandalism.

What are IK Ratings?

The standard scale originally ran from IK00 (no protection) to IK10, however the scope was then increased in 2021 to include IK11, which represents 50 Joules of energy for the impact. This is the maximum that the standards give guidelines for, however it has become generally acknowledged that a set of extrapolated energy values may be used to refer to products that exceed the performance of the standards, giving an indication of the levels of performance that could be expected from products designed for particularly demanding environments.

Occasionally you may see IK10+, IK10++ or IK11+ stated to represent products that outperform the test parameters, as well as figures ranging from IK12 and higher, sometimes as high as IK22, which represents an impact of 300 Joules.

Below is a table outlining the IK standards, including extrapolated ratings that we use to test our light fittings well beyond the parameters outlined in the standards. We believe that this level of IK testing is necessary, as the impacts sustained in day-to-day usage can easily exceed the energy of an IK11 impact –

IK Rating	Energy (J)	Product Example
IK01	0.14	–
IK02	0.2	–
IK03	0.35	–
IK04	0.5	–
IK05	0.7	–
IK06	1	–
IK07	2	–
IK08	5	–
IK09	10	–
IK10	20	Iris Standard
IK11	50	Iris VLR

Values after this point (IK12 and beyond) exceed the scope of IEC 62262:2002 and are extrapolated to create a basis for assessing products that surpass the performance of international standards.

IK Rating	Energy (J)	Product Example
IK12	62.5	–
IK13	75	Como Anti-Vandal
IK14	100	Enduralux® T Bulkhead
IK15	125	Protectalux® T Linear / Cornice
IK16	150	Enduralux® X Linear
IK17	175	–
IK18	200	Iris Anti-Ligature
IK19	225	–
IK20	250	Protectalux® Linear / Round Bulkhead
IK21	275	–
IK22	300	Protectalux® X Round Bulkhead

IK Testing Light Fittings at Light Years Ahead

Of the three accepted techniques; spring hammer, pendulum (or swing hammer), vertical (or drop hammer) Light Years Ahead opt for the vertical hammer. This has numerous advantages over the other two techniques. Details for each are below –

Spring Hammer IK Test

The spring hammer is only able to test from IK01 up to IK06, as it is small and light, therefore not capable of generating the forces required for more robust testing. It uses a simple, calibrated and spring-loaded apparatus which is withdrawn to the required IK rating distance and then released to send the hammer (or bullet as it is sometimes referred to) towards the product being tested.

Pendulum Hammer (Swing Hammer) IK Test

The pendulum, or swing hammer consists of a weight attached to a nominally rigid pivoting arm, which is raised to graduated heights. It is then released to hit the product with a measurable degree of impact energy. To determine the impact force we use the gravitational potential energy (also known as GPE) equation of –

Gravitational Potential Energy = Mass * Gravitational Field Strength * Height

or –

E_p = m g h

With gravity as a constant (the standard rounds up to the nearest integer of 10 m/s²), we can then determine the velocity of the hammer being dropped from a set height, allowing us to learn the energy of the impact in Joules.

This testing technique has a number of advantages over the spring hammer, namely that greater forces can be generated so testing can range from IK01 right up to the maximum (according to the standards) of IK11, but can also be used to test beyond this on the extrapolated range.

The limit to this test is the vertical height that you can pull the mass back to, once this reaches perpendicular to the pivot this is the maximum height you can drop from – and with the axis of the pivot being specified at 1000mm this creates an upper ceiling for the force that can be applied while still adhering to the logic of the EN/IEC 60068-2-75 (BS EN60068-2-75) standards.

Vertical Hammer (Drop Hammer or Freefall Hammer) IK Test

The vertical hammer IK test is the final technique that adheres to the EN/IEC 60068-2-75 standard. As stated previously, this is the method that Light Years Ahead uses to IK test all of the light fittings designed, manufactured and assembled in-house at our UK facilities.

Although this method is unable to test for any impact below IK02 (0.2J), we consider this a somewhat negligible level of impact. This point is highlighted when considering the specialist fields that Light Years Ahead operate in; where anti-vandal and anti-ligature lighting is so important. It allows us to test to much higher levels than even the pendulum test, as factors such as the length of the pendulum swing arm aren’t then prohibitive. The only limiting factor to how much energy can be applied to the product, is the height that you can drop the weight from. This allows us to test significantly greater impacts than the forces prescribed in the IK testing standards, but all within a practical, compact floor footprint.

The chart below shows the energy levels and drop heights, as well as the suitability for each test to be able to measure the IK ratings and extrapolated IK ratings.

IK Rating	Impact energy (Joule)	Drop Height (mm)	Mass (kg)	Spring hammer	Pendulum hammer	Vertical hammer
IK00	–	–	–	–	–	–
IK01	0.14	56	0.25	Yes ✅	Yes ✅	No ❌
IK02	0.2	80	0.25	Yes ✅	Yes ✅	No ❌
IK03	0.35	140	0.25	Yes ✅	Yes ✅	Yes ✅
IK04	0.5	200	0.25	Yes ✅	Yes ✅	Yes ✅
IK05	0.7	280	0.25	Yes ✅	Yes ✅	Yes ✅
IK06	1	400	0.25	Yes ✅	Yes ✅	Yes ✅
IK07	2	400	0.5	No ❌	Yes ✅	Yes ✅
IK08	5	300	1.7	No ❌	Yes ✅	Yes ✅
IK09	10	200	5	No ❌	Yes ✅	Yes ✅
IK10	20	400	5	No ❌	Yes ✅	Yes ✅
IK11	50	500	10	No ❌	Yes ✅	Yes ✅

Values beyond this point are beyond the scope of IEC 62262:2002 and are extrapolated to create a basis for assessing products that exceed the performance of international standards.

IK Rating	Impact energy (Joule)	Drop Height (mm)	Mass (kg)	Spring hammer	Pendulum hammer	Vertical hammer
IK12	62.5	625	10	No ❌	Yes ✅	Yes ✅
IK13	75	750	10	No ❌	Yes ✅	Yes ✅
IK14	100	1000	10	No ❌	Yes ✅	Yes ✅
IK15	125	1250	10	No ❌	No ❌	Yes ✅
IK16	150	1500	10	No ❌	No ❌	Yes ✅
IK17	175	1750	10	No ❌	No ❌	Yes ✅
IK18	200	2000	10	No ❌	No ❌	Yes ✅
IK19	225	2250	10	No ❌	No ❌	Yes ✅
IK20	250	2500	10	No ❌	No ❌	Yes ✅
IK21	275	2750	10	No ❌	No ❌	Yes ✅
IK22	300	3000	10	No ❌	No ❌	Yes ✅

Within the 60068-2-75 Standard it specifies three impacts per location, however this is superseded by the 62262 standard which states that ‘The number of impacts shall be five on each exposed face’ ‘evenly distributed on the faces of the enclosure(s) under test. In no case shall more than three impacts be applied in the surroundings of the same point of the enclosure.’ Making these tests much more rigorous than the basic hammer test conditions set out in the former.

IK Ratings in Conclusion

At Light Years Ahead IK testing forms a critical part of our product design, it allows us to be confident that the light fittings and luminaires we design, manufacture and assemble are suitable for the difficult environments in which they are created to excel in.

Whether they be in a prison cell, custodial communal area, mental healthcare facility or transport setting, we know that our lights will be able to stand up to sufficient abuse and impact and that they are suitable for purpose.

Contact us today to discuss your requirements and find out what level of protection your lighting solutions require, or to find out more about our lighting products.

Open IK Test Methods Comparison Tables

IK Rating	Impact energy (Joule)	Drop Height (mm)	Mass (kg)	Spring hammer	Pendulum hammer	Vertical hammer
IK00	–	–	–	–	–	–
IK01	0.14	56	0.25	Yes ✅	Yes ✅	No ❌
IK02	0.2	80	0.25	Yes ✅	Yes ✅	No ❌
IK03	0.35	140	0.25	Yes ✅	Yes ✅	Yes ✅
IK04	0.5	200	0.25	Yes ✅	Yes ✅	Yes ✅
IK05	0.7	280	0.25	Yes ✅	Yes ✅	Yes ✅
IK06	1	400	0.25	Yes ✅	Yes ✅	Yes ✅
IK07	2	400	0.5	No ❌	Yes ✅	Yes ✅
IK08	5	300	1.7	No ❌	Yes ✅	Yes ✅
IK09	10	200	5	No ❌	Yes ✅	Yes ✅
IK10	20	400	5	No ❌	Yes ✅	Yes ✅
IK11	50	500	10	No ❌	Yes ✅	Yes ✅

Values beyond this point are beyond the scope of IEC 62262:2002 and are extrapolated to create a basis for assessing products that exceed the performance of international standards.

IK Rating	Impact energy (Joule)	Drop Height (mm)	Mass (kg)	Spring hammer	Pendulum hammer	Vertical hammer
IK12	62.5	625	10	No ❌	Yes ✅	Yes ✅
IK13	75	750	10	No ❌	Yes ✅	Yes ✅
IK14	100	1000	10	No ❌	Yes ✅	Yes ✅
IK15	125	1250	10	No ❌	No ❌	Yes ✅
IK16	150	1500	10	No ❌	No ❌	Yes ✅
IK17	175	1750	10	No ❌	No ❌	Yes ✅
IK18	200	2000	10	No ❌	No ❌	Yes ✅
IK19	225	2250	10	No ❌	No ❌	Yes ✅
IK20	250	2500	10	No ❌	No ❌	Yes ✅
IK21	275	2750	10	No ❌	No ❌	Yes ✅
IK22	300	3000	10	No ❌	No ❌	Yes ✅

IK Ratings in Conclusion

Contact us today to discuss your requirements and find out what level of protection your lighting solutions require, or to find out more about our lighting products.

Understanding IK Ratings and Their Relevance to Lighting