Complying with IS 374

What is IS 374?

The Bureau of Indian Standards (BIS) has published IS 374, which is an Indian Standard governing electric ceiling-type fans. This standard covers the performance requirements for single-phase 50 Hz AC ceiling fans for household and similar purposes. This includes fans driven by squirrel cage induction motor, capacitor type, and BLDC motor fans up to and including 250 V.

You can download the softcopy of the standard for free from the BIS website.

Why get IS 374 certified?

Ministry of Commerce and Industry after consultation with the BIS, made an announcement in the Gazette of India (CG-DL-E-14082023-248102) requiring compulsory use of Standard Mark under a license from the BIS for manufacturers of electric ceiling-type fans.

The BIS shall certify the fan manufacturers and enforce this order. Violating the order is punishable as per the provisions of the Bureau of Indian Standards Act, 2016.

We provide air delivery lab instrumentation. As part of IS 374, setting up this lab is mandatory. Find more details here.

How to comply with IS 374 for Ceiling Fan?

As per the product manual for IS 374, the manufacturer has to perform certain tests on the fan motor that they produce. Some tests must be done on every fan while some are to be done on a sampling basis with frequency ranging from daily to once in 6 months. BIS also allows a few tests to be subcontracted to an NABL lab.

List of tests to be performed on all fans produced

Earth Continuity Test

Pass a current of at least 10 A, derived from a source having a no-load voltage not exceeding 12 V (AC or DC), between the accessible earthed metal parts and the earthing terminal. In the case of a fan motor, the fan body is considered as the accessible metal part and the motor shaft is considered as the earthing terminal. Since the fan body is painted, we advise the use of a bolt for blade mounting as the accessible metal part.

Measure the voltage drop and calculate the resistance. Resistance shall not exceed 0.1 Ohms for fans.

Electric Strength Test

The insulation of the appliance is subjected to a voltage of substantially sinusoidal waveform having a frequency of approximately 50 Hz for 1 sec. The value of the test voltage for fans is 1000 V for basic insulation and 2500 V in the case of double/reinforced insulation. You can use the standard instrument available ‘HV tester’ for doing this test.

The live and neutral is connected to one terminal of the HV Tester and the other terminal is connected to the body. The voltage is slowly increased to the required level.

No breakdown shall occur. Breakdown is assumed to occur when the current in the test circuit exceeds 5 mA. However, this limit may be increased up to 30 mA for appliances with a high leakage current

Functional Test

We inspect The correct functioning of a motor. This includes checking the direction of rotation of the motor, the functioning of the remote, etc

Simple Running Test

In this test, the manufacturer can check whether the motor is running, the motor is responding to remote commands, etc. Manufacturers can also check the power, RPM, and other performance parameter in this test.

Our product, CoFT, provides low-cost end-of-line testing for the entire production.

How to set up an Air Delivery Lab as per IS 374?

All fan manufacturers will have to set up an air delivery lab in-house and conduct performance measurements as per Clause 14.5, 15 once the Quality Control Order comes into effect. The IS 374 product manual mandates the testing of 3 samples per control unit. (All ceiling fans of one model number manufactured in a day shall constitute a control unit). For example, if you are manufacturing 3 different models in a day, you need to test 9 fans in a day.

What are the dimensions of the Air Delivery test chamber?

In order to set up the test chamber, the manufacturer will need a room of size 6.5 m x 6.5 m with a height of 4 m. Any projecting beam on the ceiling shall be above 4 m from the floor. The air delivery test chamber is a box-in-box construction.

The top of the test chamber shall be covered except for a centrally situated circular opening (top-opening), the diameter(D) of which shall be between 1.1 and 1.2 times the blade sweep. The central diaphragm in which the top opening is located shall be not more than 6 mm thick.

We provide air delivery lab instrumentation. As part of IS 374, setting up this lab is mandatory. Find more details here.

Which measuring instruments should you use?

The air movement shall be measured by means of the rotating vane anemometer having an internal diameter not exceeding 80 mm. Digital anemometers are popularly used for this application. The handset device shall have the provision of a selector switch having the option to select a measurement pulse of two seconds to sixteen seconds.

Readings shall be taken along each of the four semi-diagonals of the test chamber commencing at a point of 40 mm from the vertical axis of the fan motor by increments of 80 mm so that each reading represents an air velocity at the mean radius of the annulus 80 mm wide. After the stabilization period of 2 minutes, eight readings shall be taken in each position of the annulus on the semi-diagonals at sixteen seconds pulse.

From the velocity measurement data, the air delivery in CMM can be calculated as per Annexure B of IS 374.

Convert your basic anemometer into an advanced instrument using this simple add-on module. Record velocity data from a digital anemometer and display averaged data of 16-second pulse duration.

Wish to learn more about complying with IS 374?

There’s more to IS 374 – setting up your own end-of-line testing, BIS, and air delivery lab. We can help you simplify this. Our leadership team has extensive experience working with a leading fan manufacturer in India. We are committed to providing cost-effective and reliable equipment to help manufacturers comply with IS requirements.