Ref:ER/PR/AI-TH/40WBulbs

INSIGHT— The Consumer Magazine has published the test findings of its in-house comparative product testing laboratory on 13 brands of 40W GLS bulbs (10 brands of 230V and 3 brands of 250V) in its January-February 2007 issue. It has recommended Crompton, Laxman Sylvania, Osram Classic Clear, Surya Super and GE Crystal Clear as the ‘Best Buys’ among the brands tested.

Normal bulbs, technically referred to as GLS or General Lighting Service lamps, are bought and used by all sections of consumers. They are available easily in most shops selling electrical products and accessories.

13 brands were subjected to 11 tests. Some of the major findings are:

AVERAGE LIFE
When one buys a bulb, one’s main concern is how long it will last. 20 samples of each brand were tested to check the average life requirement of 960 hours, as per the BIS. Wipro Safelite (941.04 hours) and Prakash Lites (776.37 hours) failed the life test.

TOTAL AVERAGE LIFE
Consumers do not throw away the bulbs after 960 hours, hence we continued the life test till the end of the life of every individual lamp of each brand.

The samples were allowed to run for 1250 hours to check if they met the average life requirement of 960 hours as per the BIS Standard. The samples thus surviving after 1250 hours were subjected to an ‘extended life test’ to provide the information of their total life and light output to consumers. Out of 20 samples of each brand taken as per BIS specifications, 14 of Crompton and 11 each of Laxman Sylvania and Surya Super survived up to 1250 hours and thus were taken for the extended life test. Other brands tested for extended life were Osram, GE, Bajaj and Cema.

Laxman Sylvania recorded the highest total average life of 1337.65 hours, followed by Crompton with 1330.26 hours.

INITIAL WATTAGE
The consumption of electricity is another major concern for the user of any electrical product. Consuming more wattage than that marked on the bulbs means higher electricity bills. The consumption by a 40W bulb should not be more than 42.1W.

We found Diamond defaulting. Its consumption ranged from 43.42 to 46.12W.

CLAIMS vs FACTS
In spite of carrying the ISI mark, all the samples of Wipro failed in the marking requirements. Also its average life was found to be 941.04 hours while the Standard requires a minimum of 960 hours.

Prakash Lites also bears the ISI mark, but had an average life of 776.37 hours.

Surya Super claimed to have a ‘long life’. The tests found the total average life was 1232.36 hours, while Laxman Sylvania and Crompton had the total average life of 1337.65 hrs. and 1330.26 hrs. respectively. Many such claims of other manufacturers have been exposed in INSIGHT.

LUMEN MAINTENANCE
The Standard requires all bulbs to maintain minimum lumen (light output) of 85% (of the initial lumen) at 750 +25 hrs. Crompton maintained the highest at 95.36%.

ENERGY COST
Energy cost per year year is found to be lawest in Philips (Rs.937.20) and Bajaj (Rs. 937.67) and highest in Diamond (Rs. 1032.75).

EFFICACY
The bulb that consumes the least power but gives the maximum light is to be considered the most efficient. Higher efficacy means quality light output with lower energy consumption and thus less energy bills. Though there are no prescribed Indian Standards for this, we measured the efficacy at 1250 hours. Bajaj gave the highest efficacy at 10.42 and Laxman Sylvania had the lowest amongst all at 8.79.

MARKING
The markings on all the samples of Wipro Safelite came off the glass surface even on normal handling. The Standard requires that the markings should be ‘legible’ and ‘indelible’.

Orient bulbs were marked 40W but its wrappers had the mark of ‘25W, 215 lumen’, which should have been ‘40W, 410 lumen’ !

Thus Wipro Safelite and Orient did not comply with the requirements of marking.

The brands were tested also for mechanical and physical characteristics, lamp dimensions, control of interchangeability and safety, torsion, insulation resistance, solder, ageing and torsion test after 1250 hours. All the brands conformed to these parameters.

As a policy, before publishing and publicising the results, we convey the test findings to all the manufacturers for their views and comments. They receive the results of their own products only.

Wipro Ltd. regarding the failure in life said that it had not observed any such failure in its internal testing. The company added that it had verified its process records and the average life observed was 1140 hours. As per the lamp batch sampling life test done, the life observed was 1080 hours. In our tests, the life of Wipro Safelite bulbs was 941.04 hours. The company, concerned about the results, assured us of examining the samples to ascertain the failure mode.

Details of the rating and ranking, the ‘best buy’ and excerpts of our correspondence with manufacturers have been published in the January-February 2007 issue of INSIGHT — The Consumer Magazine.

Date : 24/01/2007
Place : Ahmedabad

Pritee Shah
Editor
INSIGHT — The Consumer Magazine

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Annexure : Table on Rating-Rating & Best Buys (click for Detail Table)
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Brands Tested

The brands tested were —— Crompton, Laxman Sylvania, Osram Classic Clear, Surya Super, GE Crystal Clear, New CEMA Super, Wipro Safelite, Bajaj, Philips Classictone Clear and Anchor in the 230 Volts category. Orient, Diamond and Prakash Lites were tested in the 250 Volts category.

Standards : The laboratory tested the 40W GLS Bulbs against the Indian Standards IS:418-1978 with seven amendments.

The sample bulbs needed to pass all the tests for the general qualities to conform to the Standards. Five additional tests were also carried out, though not given in the Standard, for providing more information to the consumers.