When waiting for metal halide (MH) lights to warm up it can take some time for them to achieve their full lighting output. This is why owners of large spaces turn them on in advance of when they are needed.
Metal halide (MH) lamps normally need an average time allowance of 1 – 15 minutes to reach full lighting output. This time period is generally called the warm-up time. If a lamp has been on for a period of time but then turned off, it can not be turned back on immediately. This is because the arc tube needs time to cool down before turning it back on. This resting period is called the restrike time. Restrike time for traditional lamps can take around 15 minutes and sometimes longer. If the lamp is running pulse-start MH lamps technology the restrike time is generally much quicker.
When a metal halide lamp is warming up it will start to be very dim to start, this state of dimness turns very slowly into a full beam of light. The main reason for this is the mechanical construction of the light fixture. Metal halide is classified as an ark lamp. However, it does function quite similarly to high-intensity discharge (HID) lights. The halide lamp works by special salts inside the tube (composed of mercury and metal halides) which are vaporized into a plasma state during the operation of the lamp. To operate effectively the lamp has to heat up to an outstanding temperature (several thousand degrees celsius). When the lamp heats up to operating temperature the salts evaporate and the light output changes. This can take some time, thus the warm-up time.
While metal halide lamps have proven very popular for lighting large spaces, they are now being superseded by LED lighting technology. Metal halide lamps do have their benefits one being high-quality light, however, there are cons as well. For example, metal halide lights use a large amount of energy when comparing them to LEDs and they also cannot be turned back on immediately after they have been turned off.
If you are thinking about changing your metal halide lights to LED and need some advice, then feel free to contact Warehouse Fit Out Solutions, who will be more than happy to assist you in your lighting project.