Commercial & industrial lamps – pros & cons
Author: Glenn Harper
Published: July 2, 2014
Investment in lighting is important for any industrial or commercial premises. Practical benefits aside, the right choices will minimise running costs and strengthen profits. Linear fluorescent and HID (High Intensity Discharge) lights are the norm in this sector, though LED technology is gaining in popularity. This article looks at various commercial and industrial lamps and weighs up their pros and cons.
HID lamps produce light by creating an electric arc between two electrodes in a gas-filled tube. They are a particularly powerful light source, used for car parks, gyms, factories, football stadiums, paths, roads, and warehouses. There are various types of HID lamp, as follows.
Metal Halide lamps last from 7,500 to 20,000 hours and are used in sports stadiums and car parks. They are also a good choice for warehouses and other high bay indoor purposes. The lamps produce a crisp white light and offer a good standard of colour rendering with typical CRI 60 to 70 scores. A choice of colour temperatures is possible, from warm white to daylight. With a luminous efficacy of between 80 and 120 lumens per watt, these lamps match the best LED or fluorescent products for energy efficiency.
A typical example of a metal halide lamp is the Venture 250W Double Ended Metal Halide, which has a cool 4200K colour temperature that’s ideal for work areas and sports activities.
The main disadvantages of metal halide lamps include light pollution, UV emission if their outer glass breaks, and use of mercury and other heavy metals.
Ceramic Metal Halide (CMH) lamps are also called ceramic discharge metal-halide lamps (CDM). The main difference between them and regular quartz metal halide lamps is that they allow a higher arc tube temperature, resulting in improved colour rendering and stability. For this reason, CDM lamps are often used in colour-critical applications such as retail display lighting, architectural lighting, or film and television.
The natural deluxe version of the G.E. 70W Double-Ended Ceramic Metal Halide boasts a CRI 90 score, which puts it ahead of most current LED products in terms of colour.
SON-E lamps are elliptically shaped, high-pressure sodium lamps. They are used in street lighting and general floodlighting. One of the main advantages of these lamps is their energy efficiency, which is shown by a luminous efficacy ranging from 65 to 140 lumens per watt. The higher end of that scale is unsurpassed by most light sources. Lifespan is also impressive with average expectancy of 15,000 to 50,000 hours. Colour temperature in these lamps is always warm.
SON lamps work with ignitors, which are either in the lamp itself (internal) or in the fitting (external). The Sylvania 250W SON-E uses an external ignitor and boasts a 24,000-hour lifespan. This lamp has a remarkable luminous efficacy of 105 lumens per watt, which equals the best LED or fluorescent products on the market for energy efficiency.
On the down-side SON lamps offer poor colour rendering. A CRI 20 to CRI 30 score reflects this, which is unusable in any setting where colour recognition is important.
SON-T lamps are tubular high-pressure sodium lamps, with the same advantages and disadvantages as SON-E varieties (above).
White-Lux SON lamps are a metal halide lamp designed to work in a standard SON fitting. The main benefit is a more natural light with a cooler colour temperature and greatly improved colour rendering. Possible uses for this lamp are identical to those listed under metal halide, including sports stadiums and halls, car parks, and warehouses. This is a fine choice for anyone who wants to upgrade light quality in an existing SON fitting without having to change either the fitting or ballast.
Mercury vapour lamps are used in applications such as warehouses, car parks, stadia and other large-scale industrial buildings. They are a type of gas discharge lamp that uses an electric arc through vaporised mercury to emit light. A white phosphor coating is often used on the outer lamp to generate an intense white light.
The main drawbacks of high-pressure mercury vapour lamps are their slow 4-7 minute warm-up time, middling energy efficiency (about 50 lumens per watt), and inferior colour rendering compared to metal halide lamps.
Dual SON & Mercury lamps are dual metal halide lamps that can be used in either SON or mercury fittings for superior performance. They give a whiter, crisper light with improved colour rendering, and this is achievable without the cost of installing new light fittings or control gear. Suitable applications include factories, retail environments and sports halls.
White SON [SDW-T] lamps run at a higher pressure and temperature than regular SON lamps to achieve a superior standard of colour rendering. Manufactured by Philips, they usually carry a minimum CRI 80 score, which extends their suitability to applications such as downlighting, display lighting, and café or restaurant lighting.
There are disadvantages with White SON lamps, however, including high upfront cost and reduced energy efficiency. Our Philips models have a luminous efficacy of about 50 lumens per watt, which is less than half that of some HID lamps and is roughly equal to low-end LED or fluorescent lighting.
SOX (low-pressure sodium) lamps are gas discharge lamps that use sodium and neon gas to produce yellow light. These are the most energy-efficient of all artificial light sources, with typical luminous efficacies of between 100 and 180 lumens per watt. They are ideal for applications such as airports, harbours, foundries, orientation lighting, quarries, railway marshalling yards and crossings, rolling mills, security, and street lighting.
The main downside of a SOX lamp is its monochromatic light, which makes it impossible to discern colour in the absence of any other light source. For that reason, it’s a poor choice of lamp in any setting with colour safety markings or where crime prevention is needed.
LED commercial and industrial lighting often comes in the form of dedicated LED fittings, which are so long-lived that they do not take replacement bulbs. The whole fitting is replaced at the end of its useful life. LED lighting is naturally directional and thus easy to control. For that reason, dedicated LED fittings are uncommonly efficient in delivering light and less wasteful than other sources.
Disadvantages of LED include greater upfront cost and lower energy efficiency at source than some rival products (the best LED lighting cannot match the lumens per watt performance of sodium lamps). On average, colour rendering is likely to be better in a ceramic metal halide lamp; most LED products have an approximate CRI 80 score.
Linear Fluorescent Lamps
Fluorescent tubes have long been popular in industrial and commercial environments as a cheap source of diffuse light. Lyco stocks a variety of surface-mounted fluorescent fittings to house them, some of which are usable outdoors. The main disadvantage of fluorescent lamps against HID lamps is that they produce less light, so you’ll theoretically need more fittings to provide the same coverage. They are also adversely affected by hot or cold temperatures, resulting in lower light levels. Linear fluorescent lighting is ideal for corridors, tunnels, and aisles.
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