The Importance of IK Rating in Lighting Fixtures Relative to Mechanical Impact and Durability

Mechanical damage to a lighting fixture may disrupt proper functioning of the luminaire or in extreme cases make the luminaire completely inoperable. When blunt force affects a luminaire, it can lead to many problems including:  critical failure to the diffuser, bent heat sink, misalignment of beam angle, destruction of outer casing, damage to origin of light source (in LED, chip set), and structural damage to lens or core components

For these listed reasons, and many more, it is extremely important that a fixture be manufactured to exacting standards, but also tested after manufacture to make certain that key stress points are built to withstand significant trauma. This testing is a vital part of producing a completed, long-lasting, quality luminaire and is a standard that is expressed by what is known as an IK rating. While many manufacturers are quick to point out the importance of IP (ingress protection) ratings as they relate to protection against dust, debris, moisture, etc. within a fixture, many neglect to mention, test for, or design and produce luminaires that achieve ratings consistent with top performance when outside mechanical trauma is introduced to the fixture. What is also often overlooked is that even an excellent IP rating can become a moot standard if the fixture’s ability to withstand mechanical damage is poor. When catastrophic structural mechanical damage occurs, ingress protection is often compromised, and in fact may be rendered useless. If a lens, cover, or other key exterior part of a fixture is broken or cracked, moisture, debris, dust, or virtually any airborne particle or liquid with exposure to said fixture is likely to penetrate the luminaire. So, while IP is a critical standard, the absence of adequate mechanical protection can nullify the effectivity of the IP abilities.

The international standard for measurement of protection against external mechanical damage is the IK Code classification as defined by IEC 62262. This standard specifies the classification of an enclosure’s impact resistance or the level of stress/effect of energy on the enclosure from the outside. The IK Code is a two-digit number ranging from 00 to 10 with the higher numeric offering the greater measurement of protection. The units used to provide this measure are “joules.” A joule (J) is a derived unit of energy in the International System of Units. It is equal to the energy transferred to (or work done on) an object when a force of one newton acts on that object in the direction of its motion through a distance of one meter (1 newton meter or N⋅m). It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889) (Wikipedia source).

While the application of an IK rating to a luminaire is considered a performance issue and is not directly related to the safety provisions of IEC 60598 standards covering luminaire safety, IK ratings are immensely important when considering the factors for durability in a luminaire. The information below explains the various degrees of IK ratings and what protective rating each represents.

·         IK Code Impact Energy (J) Equivalent Impact IK00 (no protection) – No Test

·         IK01 0.14 Drop of 200 g object from 7.5 cm

·         IK02 0.2 Drop of 200 g object from 10 cm

·         IK03 0.35 Drop of 200 g object from 17.5 cm

·         IK04 0.5 Drop of 200 g object from 25 cm

·         IK05 0.7 Drop of 200 g object from 35 cm

·         IK06 1.0 Drop of 500 g object from 20 cm

·         IK07 2.0 Drop of 500 g object from 40 cm

·         IK08 5.0 Drop of 1700 g object from 29.5 cm

·         IK09 10.0 Drop of 5000 g object from 20 cm

·         IK10 20 Drop of 5000 g object from 40 cm

While this information primarily addresses the impact created by the “drop” of an object from a distance, the truest quantifiable assessment is that external mechanical force can be created in a variety of ways, and in many environments ranging from drops to sudden mechanical impact such as the force of something hitting the housing of a fixture or luminaire. This can be particularly important, and troublesome in certain environments where rigorous or dangerous mass may be exerted simply by the nature of the installation.

For example, in seafaring applications where flood lights are employed either on a nautical vessel such as a commercial fishing boat, ice breaker, or even in shipyards or on dredges, one must be concerned not only with corrosive agents that can act against the effectiveness of the flood light, but also the opportunity for the luminaire to be mechanically impacted by outside force is amplified. For example, ice, cranes, or even the movement of heavy onboard equipment multiply the chances for potential trauma to be introduced. This can lead to failure in the fixture, but more importantly, that failure can create an environment that is potentially hazardous or creates unsafe operations for a vessel or piece of equipment.

SONARAY has many fixtures that are IK09 rated which means they are near the very top of the scale for impact resistance. This is accomplished through high-quality, ultrareliable materials, precise engineering, and quality testing that assures SONARAY fixtures are designed for ruggedness.

For example, the Delta Series 250-watt High Bay shown here carries an IK09 rating, as do all the SONARAY Delta Series Flood Light Fixtures and most SONARAY Delta Series High Bay Fixtures. The Delta High Bay Fixtures offer a unique and ruggedized design with COB chip set architecture and heat sinks that are specifically formulated to be both durable and functional in high intensity environments. The advantage of this series of luminaire relative to its IK rating means that the fixture is well protected against drops, ancillary potential impactful debris, and is well suited to perform exceptionally well in industrial manufacturing or warehousing environments where toughness really matters. Typical applications might land this fixture in steel mills, automobile manufacturing plants, or other high intensity environments where IK rating may be just as important as IP.

The Delta Flood Light Fixtures range in wattage size from 30-watts all the way up to 520-watts and are often found in venues such as truck stops for area lighting, maritime applications, on bridges, or other areas where harsh climate mandates not only an aggressive approach with IP fulfillment, but where a highly rated impact protection luminaire will work well in wind, with the possibility of flying debris, and other possible sources of external mechanical fault. The 520-watt flood light has been used in some of the toughest applications in the world including fishing applications on the Bering Strait and in high traffic logistics ports such as the Port of Cristóbal in Colon, Panama. This port is a busy and rugged environment for trade throughout the LAT and North America region. Not only does the 520- watt Delta Flood Light give this customer a variety of beam angles and nearly 60,000 lumens of light output, but the aggressive design and built-in toughness provides durability that competing fixtures cannot match.

A High IK is a Smart Choice IK rating is a separation point for SONARAY fixtures when compared with other luminaires in the marketplace. This important measurement of an added durability feature shows empirical data that not all fixtures out there are created equally. IK is a real and important element to consider for customers who not only want, but need a fixture that is clear, bright, energy-saving, safe, and provides the added benefit of extreme toughness.

When looking at applications where higher IK ratings might be most beneficial, here are a few environments that might be worth considering:

➢ Construction Sites – Heavy equipment means lots of moving parts and machinery. Flood lights with a higher IK rating make the work environment safer in “hard hat” areas for road crews, construction personnel, and traffic on roadways in and around heavy construction zone sites.

 ➢ Shipyards and Ports – Not many environments are more demanding for fixtures than those that combine for heavy machinery, corrosive agents, and busy activity. Heavy cranes and rigging are commonplace in this type of environment and exceptionally tough lighting means more safety, less downtime, and enhanced productivity. Elements including salt spray, wind, potential flying debris, and more, mean that lighting fixtures need to be tough.

➢ Heavy Industrial Warehouses and Plants – Heavy manufacturing, extrusion facilities, high ceilings, heat, cold, moving equipment, and tight timelines mean that rugged durability is a “must have” to operate most productively and safely.

In summary, IK rating for lighting fixtures is a sometimes overlooked, but especially important element to consider for safety and longstanding performance. Mechanical trauma is a very real and critical factor in many environments and there is a difference in luminaire safety and durability with mechanical impact protection ability being a verifiable separation point for consideration. When choosing fixtures, consider the implications of IP and IK testing and rating.