Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

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“Invent a New India Using Knowledge”

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“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

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“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 5799 (1970): Windvane [PGD 21: MeteorologicalInstruments]

. Is : 5799 - 1970

Indian Standard SPECIFICATIOti FOR

WINDVANE

Meteorological Instruments Sectional Committee, EDC 69

Chairman Representing

MLBA.hhNI India Meteorological Department, New Delhi

Members

Sitar N. R. CMK~AE~RT~ The National Instruments Ltd, Calcutta SARI N. R. DAS GIJPTA ( Alternate )

D~PVTY DIRECTOR ( METIXOROLO~Y ) Indian Navy STAFP OFFI~JJR ( METEOROLOGY ) ( Alternate )

JOINT DSRHCTOR, RIE.EARM ( B & F ) Research, Designs & Standards Organization ( Ministry of Railways ) , Lucknow

DEPU~ DIRECTOR, RESEARCH (B & F~) ( Alfematr )

DnR.N.M~rnnu Central Scientific Instruments Organisatioa ( CSIR ) ,

SHRI D. D. hrru ( Alternate)

SHIU R. H. MF.NIXNSA

Chandigarh

Lawrence & Mayo ( India) Private Limited, Calcutta

Snnr S. VAPADNUJAN ( Alternate )

sliul PREM PMKAsH Smu OM P-H ( Alternaf~ )

National Physical Laboratory ( CSIR ), New Delhi

SHRI K. K. ROEIATGI Government Precision Instruments Factory, Calcutta

GP GAPT S. DAS SARMA Indian Air Force WC &R P. SIUNIVASAN ( Alternate)

SHRI M. V. PATAUXAR Director ( Mech Engg )

Director General, IS1 ( Ex-@cio Member)

SIcretorg

SHRI S. M. RAZ~I

Deputy Director ( Mech Engg ), IS1

INDIAN STANDARDS INSTITUTION MANi4.K BHAVAN, 9 BAHADUR SHNi ZAFAR MARG

NEW DRLHI

15:5799-1970

Indian Standard SPECIFICATION FOR

WINDVANE

0. FOREWORD

0.1 This Indian Standard was adopted by the Indian Standards Institution on 4 September 1970, after the draft finalized by the Meteorological Instruments Sectional Committee had been approved by the Mechanical Engineering Division Council.

0.2 The direction of wind is specified relative to the true north at the place of observation and is generally expressed as a bearing in degrees from true north ( in clockwise direction ) or as a compass point using 8, 16 or 32 points according to the accuracy required. The measurement of wind direction is of great importance in meteorological research and practice and in transport, shipping, industry, engineering and various fields of human activity. A windvane is used for indicating the direction from which the wind is blowing.

0.3 The desirable properties of a windvane are as follows:

a) It should turn about its pivot with the minimum friction, l

b) It should be properly balanced with its support truly vertical, c) It should have the maximum torque for a given change in wind

direction in relation to its moment of inertia, and .

d) It should not have resonance to natural fluctuations of the wind and should be sufficiently damped to make it approximately dead- beat.

0.4 Specifications for windvanes in use at meteorological stations in the country have been prepared by the India Meteorological Department, but no Indian Standard specifications for these exist. With the increasing demand for these instruments and their manufacture in the country, the formulation of an Indian Standard for windvanes and their certification by IS1 have become necessary.

0.5 This standard has therefore been prepared in the interests of standard- ization of windvanes in use in the country and of accuracy in. the measure- ment of wind direction. The test of all windvanes made in the country and their initial certification after manufacture will in future be the sole responsibility of ISI.

i

5s : 5799 - 1970

0.6 In the formulation of this standard, due consideration has been given ta the rquirements laid down by the World Meteorological Organization, Geneva.

0.7 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, express- ing the result of a test, shall be rounded off in accordance with IS : Z-1960*. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

1. SCOPE

1.1 This standard specifies the requirements of windvanes for the measure- ment of wind directron.

2. DESCRD’TION

2.1 The windvane consists of a horizontal arm carrying a ‘rectangular flat 9n mounted by means of a thrust rod and brass bushes in a support. The horizontal arm is balanced about its axis of rotation by a counter weight attached to the end opposite to the fin. The vane and eight direction rods are supported on a suitable galvanized iron pipe threaded into a base cast- ing. Four direction arms carry the letters N, E, S and W which point towards the corresponding true directions while four direction rods indicate the intermediate directions. The position of the counter weight with respect to the 8 direction arms indicates the wind direction and may easily be determined by interpolation to the nearest 16 points of the compass.

3. MATERIAL

3.1 The material used ~for the fabrication of, the instrument shall be such that it may withstand permanent exposure in the open and have~a long life extending over a number of years. Suitable materials for the various com- ponents of the instrument are suggested below but the use of such material IS not obligatory provided the alternative material satisfies the requirements given in 7.1 and 7.2:

Material Components ( see Fig. 1 ) a) Aluminium Base, mounting ring for direction arms,

collar, arm support and horizontal arm b) Aluminium alloy Fin and bearing housing cap c) Aluminium casting Support tube ’

d) Brass Spindle and cap nut

*P&d for Fp@iIlg off nulnujcal values ( t-e&d).

3

IS : 5799 - x970

Material e) Galvanized steel f) Mild steel

g) Tin -bronze

4. DIMENSIONS

CarpOMnts Main support and direction letter Balance weight, direction arm and direc-

tion arms for letter Bearing brush

4.1 The general arrangement and main dimensions of windvane shall be as shown in Fig. 1 and 2.

Fm. 2 DETAIU OF A~ACFMENT OF DXRECT~ON ARW TO MOWNTINO Rmo OF WINDVANE

5. GENERAL REQUIREMENTS

$3 Eia and Horizontal Arm A~rcmbly -The fin shall be securely fixed to the horizontal arm at one end. The other end of the a&n shaU have a counter weight fixed in such a way that the compIetc assembly is accuratciy balanced about the spindle. The horizontal arm shall be perfectly straight. The top end of the spindle projecting up from the horizontal arm shall be hcid firmly by a suitable nut.

5.2 Bearing Housing Cap - The bearing ~housing up shall be press Wed and soldered at one end to a top cap carrying a steel guide pin aad an oii hole closed by a screw. The central hole with the step within in the bearing housing cap shall be such as to take the spindle snugly wihout pIay. Th~bcaring housing cap shal1 be locked to the spindle by n&zcf pin.

5.3 Support Tube- The support tube shall be perficctly straight. It shall hold tight a suitable ball bearing at top and have a bearing bush lowered down to serve as a bearing for the spindle. At bohtam the support tube shall be f&cd to the mounting ring for direction arms.

5.4 Spindle-The spindle shall bc a straight rod turned and finished aecuratcly such that it revclivcs in the bearing with the minim friction. The spindle shall hold tight the ball bearing ar top. It ShJi aiso be !ockcd

5

x3:5799-1970

to the bearing housing by means of a steel pin, Its extreme top shall be tapped to take the cap nut.

5.5 Mounting Ring and Directian &vans

5.5.1 The mounting ring for direction arms shall be of suitable metal and shall carry the eight cardinal and inter-cardinal direction arms. It shall be fixed to the top of the main support tube by suitable screws. _

5.5.2 The mounting ring shall rest level over a collar at the top of the main support. The collar shall be locked to the main support tube by means of a steel pin. The-mounting ring shall also be locked to the main support by suitable screws.

5.6 Main Support and Base

5i6.1 Themain support shall he a strai htgalvanixed steel pipe provided with standard pipe threads at one end or screwing into the base. The ! other end shall take the collar and mounting ring for direction arms. The main support tube shall be locked to the base by a suitable steel pin after fmal assembly.

5.6.2 The base shall be cast from aluminium or similar material. It shall have three clear holes for taking the foundation bolts.

6. WORKMANSHIP AND FINISH

6.1 All moving parts of the instrument shall be sufficiently robust to with- stand wear and tear and be so assembled as to exert minimum amount of friction.

6.2 All external surfaces shall be suitably protected with primer and finishing paint.

6.3 While any light shade of colour is acceptable for the instrument, light blue is preferred.

6.4 The ball bearings, bushings and other moving parts shall be clean and suitably lubricated with light anti-freezing lubricating oil.

6.5 The four direction letters N, E,_S and W shall be painted red.

6.6 The complete instrument shall be suitably protected to -withstand exposure in the open to widely varying climates both at inland and coastal stations.

7. TESTS AND ACCURACY

7.1 The fin and horizontal arm assembly shall be truly balanced about its axis -of rotation and shall be free from any bias towards any particular position, This test shall be carned out in a place free from draughts,

6

rs : 5799 - 1970

7.2 When the complete instrument on final assembly is held firm at bottom and the balance weight imparted an impact by a hammer weighing 0.72 kg and having a handle length of 24-O mm, it shall make not less than five and not more than ten compiete~revolutions before coming to rest.

8. MARKING

. 8.1 Each windvane shall have a name plate screwed or cemented to the bearing housing cap. The following shall be engraved on the name plate:

a) Manufacturer’s name or recognized trade-mark; and

b) Serial number and year of manufacture, for example, No. 12311969.

8.1.1 The windvane may also be marked with the IS1 Certification Mark.

Nozz - The use of the IS1 Certification Mark is governed by the provisions of the Indian Standards Institution ( Certification Marks ) Act, and the Rules and Regulations made thereunder. Presence of this mark on products covered by an Indian Standard conveys the assurance that~they have been produced to comply with the requirements of that standard, under a well-defined system of inspection, testing and quality control during production. Thii system, which is devised and supervised by IS1 and operated by the producer, has the further safeguard that the products as actually marketed are continuously checked by ISI for conformity to the standard. Details of conditions, under which a licence for the use of the IS1 Certification Mark may be granted to manu- tacturers or processors, may be obtained from the indian Standards Institution.

9. PACKING

9.1 The instrument shall be dismantled before packing by detaching the fin from the horizontal arm and the direction rods from the mounting ring. The components shall then be packed securely in a strong wooden transit case providedwith separate comparfments for the fin, arm, and the main support Cube with base. The packing shall be such that the instrument is able to withstand all possible normal transit risks. Alternately, the wind- vane shall be packed as agreed to between the supplier and the purchaser.

10. TESTING AND INSPECTJON

10.1 Each windvane shall be tested individually for conformity to all the requirements of this specification.