Tungsten Lamp Testing: BIS IS 418 Tests, Process and Tips

• Tungsten lamp testing means checking a general service filament bulb for safety, performance and marking before it is sold.
• In India, the main standards are IS 418 (performance) and IS 15518 Part 1 (safety).
• Testing is done in two places: the factory’s own lab, and a BIS recognised lab.
• Most failures come from simple things like wrong marking, weak caps and poor filament quality.
• Keep your records, calibration reports and sample details ready before you start.
• Always check the current BIS notification once before applying, because rules and lab scopes can change.

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Introduction

Think of it like a school exam. The student may say he knows everything, but the paper tells the truth. Tungsten lamp testing is that paper for your bulb.

In this blog, we will go step by step. What is tested, which standards apply, how the process works, where people fail, and how you can avoid it. Everything is in very simple words, so even a first-time applicant can follow.

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What Is Tungsten Lamp Testing?

A tungsten lamp is the old-style bulb we all grew up with. Inside the glass, a thin coil of tungsten wire (the filament) gets very hot when current passes through it. It glows and gives light. This is why it is also called an incandescent lamp or GLS (general lighting service) lamp.

Tungsten lamp testing is a set of checks done on sample bulbs in a lab. The lab checks things like:

• Does the bulb have correct markings on it?
• Does the cap fit properly in the holder?
• Is it safe from electric shock?
• Does it give the light it claims, at the power it claims?
• Does it last as long as the rated life?

If the bulb passes, the test report supports your BIS application. If it fails, you fix the issue and test again.

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Tungsten Lamp vs Other Lamp Types

People often mix these up. Each type has its own standard, so first confirm what you are actually making or selling.

Lamp Type	How It Gives Light	Simple Point
Tungsten filament (GLS)	Heated tungsten coil	Old style bulb, covered by IS 418 and IS 15518 Part 1
Tungsten halogen	Tungsten coil with halogen gas	Different standards apply, do not assume IS 418
CFL	Gas discharge and phosphor coating	Needs a different standard
LED lamp	Light emitting diodes with a driver	Has its own safety and performance standards

If your product is a normal filament bulb, this blog is for you. For other types, check the correct standard first.

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Which Standards Apply?

Two main standards are used for tungsten filament lamps in India.

Standard	What It Covers	In Simple Words
IS 418:2004	Tungsten filament lamps for domestic and similar general lighting purposes (performance)	Light output, power, life, dimensions, marking
IS 15518 (Part 1):2004	Safety requirements for incandescent lamps, tungsten filament lamps	Shock safety, insulation, strength of cap, heat and fire resistance

Besides these, some supporting standards are referred inside them. For example, there are standards for lamp cap dimensions, cap temperature rise measurement and sampling plans.

A simple example: Suppose you make a 60 W, 230 V bulb with a B22 cap. The lab will test it against IS 418 for light, power and life, and against IS 15518 Part 1 for safety. Both reports are needed.

Note: IS 418:2004 has been amended after it was published, so always use the latest amendment. Also check the BIS website once to confirm the current status of the product under the certification scheme before you apply.

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Why Is Tungsten Lamp Testing Important?

• Safety first: A badly made cap or weak insulation can give shock or start a fire.
• Legal need: Products covered under the BIS scheme need proper testing to get the licence.
• Brand trust: A bulb that fails early brings returns and bad reviews.
• Fewer rejections: If you test early, you find defects before the market finds them.
• Better planning: Test results tell you which raw material or process needs improvement.
• Smooth audits: Good test records make factory inspection much easier.

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What Tests Are Conducted?

Below is a simple view of the test groups. The exact list and clauses are in the standards, and the lab will follow them.

Test Group	What the Lab Checks	In Simple Words
Marking	Rated voltage, wattage, manufacturer name or mark, other required details	Is everything written clearly and does it stay after rubbing?
Dimensions and cap	Bulb size, cap type, fit in gauge	Will it fit the holder properly?
Protection against shock	Live parts cannot be touched when lamp is fitted	Can a finger reach any live part?
Insulation and electric strength	Insulation resistance and high voltage withstand	Does the lamp stay safe under high voltage?
Mechanical strength of cap	Torque and fixing strength	Does the cap stay firmly on the bulb?
Cap temperature rise	Heating at the cap during operation	Does the cap get too hot?
Heat and fire resistance	Resistance of insulating parts to heat and fire	Will it burn or soften under heat?
Electrical and light performance	Power consumption, luminous flux, efficacy	Does it give the claimed light at the claimed power?
Life test	Burning hours until failure	How long does the bulb really last?

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Performance Parameters Explained Simply

These words come up again and again in a test report. Here is what they mean.

Term	Meaning in Simple Words
Rated voltage	The voltage the bulb is made for, for example 230 V
Rated wattage	The power the bulb is meant to use, for example 60 W
Luminous flux	Total light given by the bulb, measured in lumens
Luminous efficacy	Light given per watt used, in lumens per watt
Rated life	The number of burning hours the maker claims
Lumen maintenance	How well the bulb keeps its brightness as it ages
Cap temperature rise	How much hotter the cap gets compared to room temperature

The lab compares your actual measured values with the limits in the standard. Small differences are allowed, but only within the permitted tolerance.

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Two Kinds of Testing: Factory Lab and Recognised Lab

Many people get confused here, so let us make it clear.

1. In-house factory lab

The BIS scheme expects a manufacturer to have a basic testing set-up in the factory for routine checks. This is used for daily and batch-wise quality control. Equipment should be in good condition and calibrated on time.

2. BIS recognised lab

For the full set of tests, samples go to a lab recognised by BIS. This is independent testing, and the report from here carries weight. Before sending samples, confirm that the lab has tungsten filament lamps in its scope.

Simple way to remember: factory lab is for your daily control, recognised lab is for the official proof.

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Step-by-Step Process

1. Confirm the product and standard. Check that your lamp falls under IS 418 and IS 15518 Part 1, and note the rated voltage, wattage and cap type.
2. Study the standards. Read the latest versions with amendments. Mark the clauses that apply to your model.
3. Prepare the factory. Arrange raw material control, production line checks and the in-house test set-up.
4. Make sample lamps. Produce samples from regular production, not special hand-picked pieces.
5. Label the samples properly. Marking should be complete and correct on every sample.
6. Select a recognised lab. Check that it has tungsten filament lamps in its scope and ask for the sample quantity and time needed.
7. Submit samples with documents. Send the request form, sample details and any other papers the lab asks for.
8. Review the test report. If any test fails, find the root cause, correct it and retest where needed.
9. Use the report for registration. Attach the report with your BIS application and be ready for the factory inspection.

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Which BIS Registration Is Needed?

The route depends on who you are. Please check the current BIS rules for your case.

Who You Are	Usual Route	Simple Point
Indian manufacturer	Standard Mark licence for the product	Factory inspection and sample testing are part of it
Foreign manufacturer	Licence through the foreign manufacturers certification route	An authorised Indian representative is usually needed
Importer	Imports must come from a licensed manufacturer	Check labelling and licence details on each consignment
Brand owner or private label	Product must be made by a licensed factory	Brand name details must follow BIS conditions

If your model, brand name, wattage range or factory changes, the licence may need an update. Do not skip this.

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Documents Required

The exact list may change, so confirm with BIS or your consultant. In general, these are needed.

Company documents

• Business registration proof
• Factory address and ownership details
• Authorised signatory details
• Details of quality control staff

Product documents

• Model list with rated voltage, wattage and cap type
• Marking details and label drawing
• Manufacturing process flow chart
• List of raw materials and suppliers

Testing records

• Recognised lab test report
• Calibration certificates of test equipment
• In-house inspection and test records
• Raw material test records

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How Long Does It Take?

There is no single fixed time. It depends on how ready you are.

• Sample preparation and lab booking take some days.
• The life test needs real burning hours, so it takes time and cannot be rushed.
• Retesting after a failure adds more time.
• Document corrections and factory inspection scheduling also affect the total.

Start early. Keep a buffer for retesting, because it is more common than people expect.

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Cost: What Decides It?

We are not mentioning any amounts here, because they change from lab to lab and case to case. These are the main factors.

• Number of models and variants being tested
• Lab testing charges for the selected tests
• BIS application and licence charges
• Inspection and travel costs
• Retest charges, if any test fails
• Equipment calibration and in-house lab upkeep

If you want a clear breakup, ask the lab for a written quotation and check the current fee list on the BIS website.

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Common Failures and Easy Fixes

Common Failure	Why It Happens	Easy Fix
Marking fades or is missing	Poor ink or wrong printing process	Use better ink and recheck the label format
Cap loosens in strength test	Weak cementing or poor cap material	Improve cap fixing and quality of cement
Cap runs too hot	Bad contact or poor design	Check cap quality and the joining process
Life is below rated value	Poor filament or gas filling problem	Improve filament quality and the bulb process
Power consumption out of tolerance	Filament not as per design	Control filament dimensions and winding
Insulation test fails	Moisture or defective insulating material	Check material quality and storage conditions

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Common Mistakes

1. Using special hand-picked samples instead of regular production samples
2. Not reading the latest amendments of the standard
3. Incomplete or unclear marking on the bulb
4. Sending samples to a lab that does not have this product in scope
5. Expired or missing calibration of in-house instruments
6. Poor records for raw material and daily checks
7. Changing the model or raw material after testing without informing anyone
8. Starting too late and not keeping a buffer for retests

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Who Needs This?

• Manufacturers making filament lamps in India, who need testing for the licence.
• Importers who must ensure that the product comes from a licensed source.
• Private label brands who get lamps made by another factory under their own name.
• Overseas manufacturers who want to sell in India and need the right BIS route.
• Traders and distributors who want to check that the stock they sell is properly marked and certified.

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Why Choose Diligence Certifications for tungsten lamp testing Certification?

Testing and certification look simple from outside, but the real work is in the details. A wrong label, a missing document or a delayed lab slot can cost weeks.

Diligence Certifications helps you with the whole path in a practical way. The team can help you understand the standards, prepare your documents, plan the testing and keep the process organised. You can visit the Diligence Certifications homepage to know more about the company, and check the services page for the support available.

We do not promise approval, because the final decision always rests with the authority and the lab results. What we promise is clear guidance, honest advice and good follow-up at each step.

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After Registration: Market Checks

Getting the licence is not the end. BIS can check products in the market and also inspect the factory from time to time.

• Keep producing lamps in the same quality as the tested samples.
• Continue routine in-house testing and keep the records.
• Use the Standard Mark exactly as allowed in the licence.
• Inform BIS about any major change in the process, product or address.
• Renew the licence on time.

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Tips to Pass in the First Attempt

1. Read IS 418 and IS 15518 Part 1 fully before making samples.
2. Check the filament, cap and glass quality at the raw material stage.
3. Run your own pre-test on a few samples before sending to the lab.
4. Check the marking for clarity, spelling and rub resistance.
5. Make sure your instruments are calibrated and records are updated.
6. Send samples from regular production, with a proper sample record.
7. Talk to the lab beforehand about sample quantity and test schedule.
8. Keep extra time in your plan, so a retest does not disturb your launch.

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Quick Checklist Before Sending Samples

• Latest standards and amendments checked
• Model, voltage, wattage and cap type confirmed
• Marking is complete and clear
• Samples taken from regular production
• Pre-test done in the factory lab
• Calibration reports are valid
• Lab scope confirmed for this product
• Sample details and request form ready
• Documents arranged in one folder

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Conclusion

A tungsten lamp may look like a very basic product, but safe and reliable lighting does not happen by chance. Proper testing against IS 418 and IS 15518 Part 1 shows that your bulb is safe, gives the light it promises and lasts as long as it claims.

Start with the right standards, prepare your factory, test early and keep your records clean. If you do these four things, the process becomes much smoother. And if you need a guide at any point, Diligence Certifications is there to support you.

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Frequently Asked Questions