Initially related to the IP code wherein a numerical rating was added to the end of an IP rating, the IK impact rating was made distinct from the IP code to measure the impact resistance of product in 1995. IEC 62262:2002 specifies impact protection ratings as part of the IK code. Code ratings range from IK00; not protected, up to IK10; which proves that a product can withstand 20 joules of energy. This is done through specified tests like pendulum or free-fall hammers being released at precise distances and with precise weights.
|
IK code |
IK00 |
IK01-IK05 |
IK06 |
IK07 |
IK08 |
IK09 |
IK10 |
|---|---|---|---|---|---|---|---|
|
Impact energy (joules) |
* |
<1 |
1 |
2 |
5 |
10 |
20 |
|
Rmm (radius of striking element) |
* |
10 |
10 |
25 |
25 |
50 |
50 |
|
Material |
* |
Polyamide 1 |
Polyamide 1 |
Steel 2 |
Steel 2 |
Steel 2 |
Steel 2 |
|
Mass (kg) |
* |
0.2 |
0.5 |
0.5 |
1.7 |
5 |
5 |
|
Free fall height (m) |
* |
* |
* |
0.4 |
0.3 |
0.2 |
0.4 |
|
Pendulum hammer |
* |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
|
Spring hammer |
* |
Yes |
Yes |
Yes |
No |
No |
No |
|
Free fall hammer |
* |
No |
No |
Yes |
Yes |
Yes |
Yes |
The IK code test conditions.
While precise and repeatable, these figures can sometimes make it hard to understand or internalize the realistic scenarios in which IK ratings are meant to simulate. For example, when reading the parameters in an IK10 rating, 20 joules of energy is manifested by dropping a 5kg mass from 400mm above the impacted surface. Calculating the free-fall acceleration from the specified height, that’s like rolling a medium size bowling ball towards a luminaire at around 9 feet per second.
Test hammers made to IK specifications.
For most conditions, this upper limit of the IK standard is appropriate. However, there are efforts to expand the IK code higher to account for things like vandalism and other more extreme environments. Some manufacturers have begun to extrapolate existing IK data for these environments by continuing the existing data in a proportionate way, adding IK “ratings” all the way up to “IK20”.
However, what is not captured in the IK code could be the most crucial part of considering product suitability: the likely frequency and severity of a given impact.
When considering a product, it can be important to judge how likely a product is to be treated harshly and how often - much like a risk assessment. When these details are not well known, there is a tendency to “over-specify”. And very often more impact protection usually comes at a cost. This cost can be either through added weight or performance reductions. Limited focusing ability, guards which hinder output, or simply increased upfront costs are common with higher IK ratings. This is especially important when considering non-permanent usage, in which equipment will be moved or transported. Indeed, it is surprising that within the production lighting market, there is often no mention of IK ratings for very expensive equipment that is meant to be portable and transported throughout its working life. Therefore, understanding the specific impact related vulnerabilities of a product can be crucial to product suitability, and thus longevity. Look closely for design features like exposed wiring entry points, screens, indicators, or other components likely to break when subjected to impact.
Impact ratings are also key in permanent installations such as with lighting for buildings near roads. When choosing products for installation close to streets, guarding against small objects like pebbles or stones moving with relatively high speed is recommended. But on other sides of a building, which may not have roads nearby, this level of protection may not be necessary. Therefore, sourcing a product which has different IK rating versions might result in a lower total cost.
Additional considerations include understanding how a product is designed to fail during impact and the resulting repair cost. Attempting to guard against every eventuality will lead to over specifying. Understanding the possibility of repair versus replacing a product entirely can lead to significant through-life cost efficiencies during the design period.
At SGM, many products are tested to IK07 through IK09 ratings as the risk of impact in both touring and in installation projects we work in is high. Additionally, the ability to repair products is part of our core product development philosophy. Controlling the manufacturing of our product lines in house means that SGM products can almost always be repaired. From new LED engines in moving lights, to replacement of outer casings complete with new IP rated seals, to on-site performed vacuum testing, we work hard to design tough products that last, lowering the true cost for end-users.