IS 4894 FOR CENTRIFUGAL FAN PDF

Comments. IS Code. Recent; Popular; Featured. IS – – Pallets for materials. Buy BIS IS (R) SPECIFICATION FOR CENTRIFUGAL FANS from SAI Global. Standard Air. Centrifugal fans for use in mines and hazardous atmospheres may requirt: additional requirements to be met, not covered by this standard.

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The screen may be composed of one or more layers of even wire or iiabric supported by a wire guard. The resistance measurement shall be made with a current of lOA with centrjfugal dc voltage not exceeding 6V. Note — The difference in pressures is the mean pressure when facing tube reading is employed. The value of r may be taken as 1 “4 for atmospheric air.

If the number of defectives found in the first sample is less than the rejection number, take a second sample of size indicated in col 3; and if the total number of defectives dentrifugal the first and second sample put together is less than the rejection number, accept the lot, otherwise not.

Part 55 Electric fans.

The other limbs of the manometer shall be opened to the ambient atmosphere and the manometer reading shall be taken as equal to the average static pressure in the airway. The criterion of noise level may, therefore, be subject to an agreement between the manufac- turer and the purchaser. However, it has not been found possible afn specify these limits at present on account of: The fixed losses and copper losses shall be calculated in accordance with the details given in IS: Such an addition shall then be regar- ded as a part of the fan.

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Intermediate values of d, may be obtained by linear interpolation. This is normally shown in graphical fashion, following performance tests carried out in accordance with If more convenient, the flare may be remo- ved for the test.

IS 4894: Centrifugal fans

Full text of ” IS For routine and acceptance tests, instruments of class index dor may be used. Proper types of bearings should be used to ensure a reasonable amount of silent operation.

This requirement is applicable van all positions in the normal use. A system resistance line shall also be drawn, passing through the specified duty point such that the total or static pressure varies with the square of the inlet volume flow see Fig.

If the fan is specified for two or more distinct rated voltages with three or more supply terminals, the tests shall be carried out at the most unfavourable voltage.

These insulat- ing materials are detailed in IS: Manaksanstha Common to all offices Telephone,,’Sales Office in Calcutta is at 5 Chowringhee Approach, P. The openings – shall be flush with the duct and free from burrs and countersinks.

Full text of “IS Centrifugal fans”

The inlet airway diameter D used in the computation shall be measured after- manufacture. A recommended sampling plan is given in Table 3. Ceentrifugal marked products are also continuously checked by BIS for conformity to that standard as a further safeguard.

This test shall centriufgal carried out with the guard if any, in position. This revision has been undertaken to take into account the experience gained since then and to align some of the safety requirements with the provisions of IS: All metallic parts associated with it shall be protected from accidental contact.

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The method of measurement of the speed of fan shall be such that fa speed of the fan is not appreci- ably affected. When the air flow, in cubic metres per hour, is numeri- cally less than 16 times the airway diameter in metres, then the coefficient of discharge shall be taken appropriate to the Reynolds number given in Table 2. In the case of a double insulated fan, both basically insulated parts and live parts shall not be accessible to the standard test finger.

It is always positive. Never- theless, fans made to work in higher cooling air tem- peratures may be regarded as complying with this specification provided the temperature-rise values are reduced corresponding to the increase in cooling air temperature.

The most probable operating point for the fan shall be at the intersection of the fan characteri- stic and the system resistance line.

IS – – Centrifugal fans | QuestIn

This is also commonly known as wheel diameter. It is positive when above and negative when below the ambi- ent pressure. When the guards are in two pieces, positive locking arrangement to keep the two pieces together should be made.

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