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Survey and health assessment of mercury in compact fluorescent lamps and straight fluorescent lamps

2 Survey

• 2.1 Description of types of fluorescent lamps
• 2.2 Survey of quantities of mercury
• 2.3 Survey of types of mercury compounds in fluorescent lamps
• 2.4 Future developments
• 2.5 Summary

The survey of compact fluorescent lamps has been conducted through internet searches and contact to various dealers, importers, manufacturers and suppliers of compact fluorescent lamps and straight fluorescent lamps.

Internet searches

Information gathered in internet searches mostly concerned types of compact fluorescent lamps and straight fluorescent lamps as defined by different manufacturers. Only to a limited extent information about actual quantity of mercury in different products was found. Normally, manufacturers just state that they are in compliance with current legislation.

Contact to manufacturers/importers

The survey has only to a limited extent been able to clarify which form of mercury is contained in products. A limited number of importers, dealers, manufacturers and suppliers were, however, able to deliver more detailed information concerning mercury amounts and mercury compounds used in compact fluorescent lamps/straight fluorescent lamps. Table 2-1 gives an outline of information received from different manufacturers and importers through websites and personal contact.

Table 2-1. Information received from manufacturers/importers

2.1 Description of types of fluorescent lamps

Several different categories of types of compact fluorescent lamps and straight fluorescent lamps are in use. In the following the categories used in the RoHS Directive, the EU ecolabel scheme and Danish tax legislation are described along with the categories of products used by manufacturers/dealers and the Danish energy saving trust.

RoHS

The RoHS Directive (RoHS EU, 2002) distinguishes between:

• Compact Fluorescent Lamps = CFL
• Straight Fluorescent Lamps for general purposes
• Straight Fluorescent Lamps for special purposes

Ecolabel criteria

European ecolabel criteria (EU, 2002) for light bulbs divide products into the same types as the RoHS Directive. Furthermore, the ecolabel criteria divide single-ended light bulbs into the following two groups:

• Light bulbs with integral ballast (CFL compact fluorescent lamps)
• Light bulbs without integral ballast (straight fluorescent lamps - pin based lamp).

Figure 2-1 shows examples of light bulbs with integral ballast and without integral ballast. ‘Ballast’ means a device which serves mainly to limit the current of the lamp(s) to the required value in case it is connected between the supply and one or more discharge lamps. A ballast may also include means for transforming the supply voltage, dimming the lamp, correcting the effect factor and, either alone or in combination with a starting device, providing the necessary conditions for starting the lamp(s) (EU, 2009).

Light bulbs with integral ballast have a normal base, i.e. bayonet or screw base. This means that the consumer can replace incandescent bulbs with this type of lamp in their normal socket directly. Light bulbs without integral ballast (single and double-ended straight fluorescent lamps) are tubes that are pin based. Due to this pin base they can only be used in sockets designed for this type of lamp, i.e. they cannot directly replace incandescent lamps. Non-integral lamps are single-ended while straight fluorescent lamps are double-ended.

Figure 2-1. Light bulb with integral ballast (left ) and without integral ballast (right) (General Electrics, 2009).

SKAT (Danish Tax and Customs Administration)

According to SKAT’s guidelines on excise duties 2009-2 all single-ended low energy fluorescent lamps (compact fluorescent lamps) are exempted from ”excise duty on incandescent lamps etc. and electronic fuses” (Skat, 2009). SKAT thus distinguishes between compact fluorescent lamps and straight fluorescent lamps through the number of sockets:

• Compact fluorescent lamps are single-ended
• Straight fluorescent lamps are double-ended.

Straight fluorescent lamps are furthermore divided into two categories, of which one is subject to excise duty:

• ”Straight fluorescent lamps with a power of 20 or 40 watt and emitting ultraviolet light. The tube is coated on the inner side with a specific fluorescent material. Lamps are designed for use in standard sockets.”

Straight fluorescent lamps exempt from excise duty are described as:

• ”Straight fluorescent lamps with a power of 400 watt emitting ultraviolet light. The length of the tube is 12 cm and it is equipped at each end with a main and a secondary electrode. They contain mercury vapours and cannot be used directly due to the fact that they have no socket. The lamp is used in surface treatment and hardening of lacquers in industry”.

This categorisation follows that of the RoHS Directive and thus distinguishes between straight fluorescent lamps for general purposes and straight fluorescent lamps for special industrial purposes. Only the first type of straight fluorescent lamps is included in this survey.

Manufacturers/importers

Manufacturers and importers (such as Philips, 2009; Osram, 2009; Megaman, 2009) often divide compact fluorescent lamps in general types according to:

• Function, such as dimmed, night lamp, outdoor;
• Shape, such as pear, globe, candle, spiral (See Figure 2-2 for examples);
• With/without integral ballast.

Danish energy saving trust

The Danish energy saving trust also divides compact fluorescent lamps according to shape (pear, rod, other) (Elsparefonden, 2009). See Figure 2-2.

Figure 2-2: Various types of lamps. Pear (top left), globe (top right), candle (lower left) and spiral (lower right) (General Electrics, 2009).

One of the interviewed manufacturers state that pear, globe and candle shaped lamps as shown in Figure 2-2 contain a tube within the outer casing as illustrated in Figure 2-3 below.

Figure 2-3. Example of lamp with casing (from the list of A-lamps of the Danish energy saving trust)

This manufacturer states that this additional casing may be an extra protection of the consumer since in some cases only the outer glass breaks in case of accidents. On the other hand this extra casing means that the light yield (lumen value) is reduced by at least 10 % due to reflection and absorption in the outer casing. It is possible to change the absorption features of the outer casing in order to give the lamp more pleasant colour features (e.g. less bluish and more reddish spectre). According to the manufacturer no extra mercury is added to compensate for the loss of light yield (lumen).

Furthermore, the same manufacturer has stated that the compact fluorescent lamp without the extra casing is presently most popular on the market, since it is normally cheaper. The extra casing increases production costs and thus the lamp sales price.

2.2 Survey of quantities of mercury

The survey showed that quantities of mercury in fluorescent lamps vary much. Differences are seen not only from one manufacturer to the other, but also between types of lamps from the same manufacturer. No pattern has been found regarding types of lamps whether divided according to lamps with integral ballast, without integral ballast, straight fluorescent lamps or shape of lamps.

According to Manufacturer D quantities of mercury depend on the following factors some of which have an influence on quantities of mercury over time (also described by Snijkers-Hendrickx et al. (2007)):

• Size of lamp. The larger lamp the larger surface of glass and phosphor coating to be impacted by the mercury, and thereby requirement for larger quantity of mercury.
• Lifetime of the lamp. The longer lifetime the more mercury can be bound to the phosphor coating during the lifetime of the lamp.
• Use pattern. Number of switch on/off cycles. Electrodes ”consume” mercury during the life of the lamp. Long life fluorescent lamps thereby require ”surplus” mercury (Sigai & Nesting).
• Dosage technology. If mercury is added in the form of a tablet or as amalgam, more accurate quantities of mercury can be added compared with dosage of liquid mercury.
• Material composition. Different materials used for fluorescent lamps (glass, phosphor coating, etc.) have different capacity to bind mercury through the lamp life. In addition, impurities in the glass material may have a decisive role for consumption of mercury in the lamp life.
• Use of additives. Addition of antioxidants or, for example, a protective layer of aluminium oxide between the phosphor coating and the glass may help reduce quantities of mercury bound to the fluorescent lamp in the lamp life.
• Type of phosphor coating. Quantities of mercury bound to the phosphor coating depend highly on the type of phosphor coating used.

Several manufacturers also told that they are working continuously to minimise mercury contents in their products and that the content is therefore expected to decrease in the future. Thanks to improved technologies quantities of mercury can be lowered without affecting the lifetime or performance of the lamp (SAES Getters, 2009; Snijkers-Hendrickx et al., 2007). According to Snijkers-Hendrickx et al. (2007) a gradual shift in dosage technology is furthermore seen towards the use of solid mercury, i.e. in the form of tablets or as amalgam.

In Commission Regulation (EC) No. 244/2009 with regard to ecodesign requirements for non-directional household lamps it is required that the mercury content of a lamp (in mg) must be indicated as from 1 September 2010 (EU, 2009). Since mercury contents must be known in the future it may become a future competitive parameter to minimise mercury contents, even when they are below the limit values of the RoHS directive and the ecolabel criteria. Examples have been seen that manufacturers already today indicate the mercury content on their packaging. For example a 10 Watt bulb from PRO light is on the market indicating a mercury content of ”<3 mg Hg”. Some manufacturers also indicate the mercury content on their website (e.g. Philips).

Contacts to different manufacturers have given information about mercury contents between 1.2 and 4.9 mg for compact fluorescent lamps with integral ballast. For non-integral compact fluorescent lamps contents between 1.4 and 4.4 mg Hg have been given and for straight fluorescent lamps contents have been stated between 1.4 and 9.5 mg Hg. See Table 2-2. Quantities of mercury in compact fluorescent lamps differ among manufacturers. One manufacturer has stated that his compact fluorescent lamps have a maximum of 2 mg Hg and another manufacturer states that by far most of his compact fluorescent lamps (80 % of those with integrated ballast) have an average Hg content of 4 mg.

Table 2-2 Content of mercury in compact fluorescent lamps/straight fluorescent lamps – information given by manufacturers

These figures cover lamps manufactured today and thus complying as a minimum with limit values in the RoHS Directive. However, older lamps are still in use, probably with higher mercury contents. For example, old straight fluorescent lamps can contain 15-20 mg of mercury (Hansen et al., 2008).

As a matter of comparison German magazine Öko-test has tested compact fluorescent lamps in October 2008. Here, values for compact fluorescent lamps between 2 and 6 mg Hg per lamp are reported (Öko-test, 2008).

2.3 Survey of types of mercury compounds in fluorescent lamps

Three manufacturers/importers have told which mercury compounds are added to different compact fluorescent lamps and straight fluorescent lamps. The mercury is used in the fluorescent lamps either in the form of a HgFe compound, in the form of amalgam or in the form of metallic mercury.

According to the manufacturers/importers bismuth (Bi), tin (Sn), indium (In), silver (Ag), lead (Pb) and zinc (Zn) are found in different combinations in the amalgams used. Following combinations have been reported:

• ZnSnHg
• BiInHg
• BiInPbHg
• BiSnPbHg
• BiInSnAgHg
• BiInSnPbHg

Based on information from manufacturers/importers it is not possible to find a correlation between type of fluorescent lamp and type of mercury compound used.

According to Groth (2008) consumers are better protected against exposure to mercury in fluorescent lamps using encapsulation of mercury (in the form of tablets or as amalgam) compared with liquid mercury in the fluorescent lamps – due to the fact that the mercury is bound.

Compact fluorescent lamps with an extra casing also give better protection of the consumer since in some cases only the outer casing breaks during accidents in homes.

2.4 Future developments

As described in Snijkers-Hendrickx et al. (2007) manufacturers are working to reduce quantities of mercury in compact fluorescent lamps and straight fluorescent lamps, among other things through work with/research in technologies for dosage of mercury to the lamp, the materials the lamp are made of and the use of different additives. All these issues have an impact on the quantity of mercury needed in a fluorescent lamp.

Research is also made in how to reduce releases of mercury when a fluorescent lamp breaks. Lee et al. (2009) has shown that the use of a nano-selenium barrier can reduce evaporation of mercury.

The purpose of this project has merely been to focus on the risk arising from mercury-containing compact fluorescent lamps/straight fluorescent lamps breaking in homes. Therefore no further details on technological developments in this field are given here.

2.5 Summary

A brief survey of the market has been made by contacting manufacturers/importers of compact fluorescent lamps and straight fluorescent lamps, and by conducting searches on the internet.

Different types of compact fluorescent lamps and straight fluorescent lamps are available. The general categorisation is based on form (e.g. pear, globe, candle or spiral) or the function (e.g. dimmed, outdoor etc.) Another categorisation is lamps with or without integral ballast. A lamp with integral ballast has a normal fitting, i.e. bayonet or screw base that can be used in a normal socket directly.

Compact fluorescent lamps are single-ended and straight fluorescent lamps are double-ended.

Seven different manufacturers/importers of compact fluorescent lamps and straight fluorescent lamps were interviewed for information about quantities of mercury in fluorescent lamps and about types of mercury used in these lamps.

The result of the survey was the following:

• Compact fluorescent lamps can contain between 1.2 and 4.9 mg Hg per lamp
• Straight fluorescent lamps can contain between 1.4 and 9.5 mg Hg per lamp

The content of mercury in compact fluorescent lamps is typically lower than the statutory limit value of 5 mg Hg. So for the exposure calculations it will be relevant to use different values. The content of mercury in a lamp depends on many factors such as use pattern, mercury dosage technology as well as size, age, lifetime and material composition of the lamp.

Three manufacturers/importers have stated that mercury in the lamps is found in the form of a HgFe tablet, in the form of amalgam or in the form of metallic mercury. No correlation has been found between the type of lamp and the type of mercury compound used.

Some sources state that consumers are better protected against exposure to mercury in a fluorescent lamp using a HgFe tablet or amalgam compared with liquid mercury, since this mercury is bound. One manufacturer also states that a compact fluorescent lamp with extra casing can also give better protection of the consumer since in some cases only the outer casing breaks during accidents in homes.

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Version 1.0 August 2010, © Danish Environmental Protection Agency