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इंटरनेट मानक 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. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru “The Right to Information, The Right to Live” “Step Out From the Old to the New” IS 15253 (2002): Dew Gauge [PGD 21: Meteorological Instruments] “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda ““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee”” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” IS 15253:2002 IndianStandard DEW GAUGE — SPECIFICATION ,’ ICS 07.060 0 BIS2002 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 November 2002 Price Group 3 I l“ Meteorological Instruments Sectional Committee, BP 21 FOREWORD .- This IndianStandard wasadopted bytheBureauofIndianStandards,afterthedraftfinalizedbytheMeteorological i: lnstruments Sectional Committee, had been approved bythe Basic& Production Engineering Division Counci1. I The deposition of dew isessentially anocturnal phenomenon. During clear nights with calm or lowwind speed conditions, theground aswell asitsenvironment exposed toskylosesheatduetoradiation. When itstemperature tills below the saturation temperatttre ofthe surrounding air,water condenses and deposits asdew, Dew isvery crucial for the plants for their unhindered growth when seasonal rainfall israther negligible. It isan important source of moisture to plants especially in arid and semi-arid climatic zones, which receive low q,uantum of rainfall. 1nsome areas, the formation of dew itself forms an important secondary source of moisture’to the soil inthe same order of magnitude asthe rainfall ofthat place especially during non-rainy season. The fact isnow widely recognized by the agricultural scientists. Dew is responsible for the spread of many plant diseases, surface soil moisture and thus affects the world economy in variety of ways. It is an important factor in microclimate as well as in weather forecasting. $ Measurement of accumulation of dew isnow becoming an increasing demand for planning several agricultural , operations and evolving new crop strains for hydrological or hydro meteorological studies. Study of dew has attracted the attention of plant breeders, plant physiologists and agronomists the world over. Dew isusually hydroscopic and isexpressed ingrams ofmoisture deposited per 100cm2ofthe exposed surface area or generally in millimetres of dew. One millimetre of condensed moisture inthe form of dew corresponds to 10gof dew deposited/100 cm2. While preparing this standard considerable assistance had been provided by lMA Hyderabad. ~ For the purpose of deciding whether aparticular requirement of this standard iscomplied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS2: 1960 ‘Rules for rounding off numerical values (revised)’. Thenumber ofsignificant piaces retained inthe (; rounded off value should be the same asthat of the specified value inthis standard. IS 15253:2002 IndianStandard DEW GAUGE — SPECIFICATION 2.2 The dew gauge consists of rectangular blocks of 1 SCOPE wood coated with red oxide paint, which favours Thisstandardspecifies therequirements ofdewgauge retention of dew deposit on them. During the dew for themeasurements of dew. season, the dew gauge isexposed on a suitable stand atabout sunset and the size, form and distribution of 2 DESCRIPTION dew deposited during the night are observed before 2.1 The general structure ofthe dewgauge shallbe as the sunrise next day. These observations of shown in Fig 1. characteristic distribution ofdrops ofdewontheupper GAUGE .-.--.” ., Alldimensions in millimetres. FIG. 1DEW GAUGE ASSEMBLY 1 IS 15253:2002 and IGWsurfaces of the block are compared with a brassscrewsexactly attheheights of50mm,250mm, seriesofstandard full-scale photographs ofdewstypes. 500 mm and 1000 mm from the ground level. The photographs bear the dew scales 1to 8 and the 3.2.2 The supports and clamping arrangements shall dew scales are converted into equivalent amount of bepaintedwithsufficient coating ofwhiterubberpaint moisture inmillimetres by a suitable table. to prevent corrosion or absorption of heat due to 3 MATERIAL radiation. 3.1 Dew Gauge 3.3 Stand The dewgauge shallbemade ofsuitable wood having Thevertical standforthedewgauge andthebaseshall the following properties: be of non-rusting, non-magnetic and non-corrosive stainless steel or similar material. a) Having rigidity and strength with no distortion or deformation or any other 3.3.1 The vertical stand shall be made of tube of deterioration when exposed to very low suitable strength. temperature conditions inthe open air while 3.3.1.1 Alternatively, the dew gauge stand can also at the same time being light in weight. suitably bemade intwo pieces sothat one piece rest b) Freedom from attack of animals, birds, snugly into the other without any gap or protrusions insects or fungoidal life. outside, however, the total height should remain the c) Smooth surface finish to ensure uniform same asshown in Fig. 1. coating of good quality of red oxide paint. 3.3.2 The base shall be made up of asingle plate. d) Low thermal conductivity so asto minimize the loss of evaporation. 3.3.3 The stand shallbe fixed vertically onthe centre ofthe base plate with suitable threading arrangement e) Material, which necessarily differs in its into the base sothat the height ofthe stand above the thermal properties from the surrounding air. ground level shall be exactly 1100mm. o Material shall be as simple as possible and shall preserve the dew until such time as an 3.3.4 Thestandshallbepainted withsufficient coating observer can conveniently go outside to of white rubber paint to prevent absorption of heat record it. due to radiation. 3.1.1 The rectangular blocks of wood shall be made 3.3.5 The base ofthe stand shall also be painted with ,----- up of only one single piece of.solid, plain teak wood, suftlcient coating of a suitable anti-corrosive paint. free from scratches, wrinkles, dents, cavities, hollow or holes. The material shall be such that it iscapable 4 DIMENSIONS AND TOLERANCES of withstanding the weathering effects ofexposure in 4.1Thedimensionsforthedewgauge, supports, clamp open air for long period. andvertical standwithbaseshallbeasgiven inFig. 2, 3.1.2 Agroove each of 5mm x 10mm shall bemade 3and4respectively. on side ‘B’ at a distance of 48 mm from either edges 4.2 The dimensions shall be correct to within +1 mm of the dew gauge throughout its width so that it site of the specified value given in Fig. 2, 3 and 4 firmly on the support. respectively. 3.1.3 Thesurfaces ofthedewgauge shallnotbegreasy oroily ordusty. 5DESIGNATION 3.1.4 The rectangular blocks of wood shall be coated Forthepurpose ofinquiry ororder, thewooden block, with a uniform coating of suitable good quality red supports and vertical stand with base shall be totally oxide paint several times tillthey areperfectly smooth designated as ‘Dew Gauge’. inorder toretain theproper deposition ofdewontheir 6 GENERAL REQUIREMENTS surfaces. 6.1 Each rectangular block of dew gauge has to be 3.2 Support and Clamp placed on fixed supports provided at the heights of The supports and clamps for the dew gauge shall be 50mm, 250 mm, 500 mm and 1000 mm from the of non-rusting, non-magnetic and non-corrosive ground level. The vertical heights being measured stainless steel or similar material, from the ground tothe centre of the dew gauge. 3.2.1 The supports shall be firmly level mounted on 6.2 The dew gauge supports shall be level-mounted the vertical stand inopposite directions alternately by inopposite direction alternately. 2 IS 15253:2002 320 320 4 - A 25 5 I 3 +0 +0 I 10 48-1 48--1 B 204 . AHdimensions in millimetres FIG.2 DEW GAUGE ~,----- 6.3 The dew gauge stand shall be fixed perfectly Top with ‘A’and bottom with ‘B’. vertical with the base embedded inthe ground. 8.3 BIS Certification Marking 7TESTING AND INSPECTION 8.3.1 The product conform to this standard may also All the dew gauges shall be ind ividually tested for be marked with the Standard Mark. conformity toalltherequirements of thisspecification 8.3.2 The use of the Standard Mark is governed by andshallcarryacertificate from acompetent authority tothis effect. theprovisions ofBureau ofIndiarr Standards Act, 1986 and the Rules and Regulations made thereunder. The 8 MARKING details of conditions under which the Iicence for the useofStandardMarkmaybe granted tomanufacturers 8.1 Each dew gauge shall bear the following of producers may be obtained from the Bureau of inscription engraved legibly and neatly on a brass name plate of suitable size and shall be cemented Indian Standards. firmly onthe vertical stand: 9PACKING a) The inscription DEW GAUGE; The four blocks of dew gauges shall be wrapped in b) Serial No. and the year of manufacture; and thick tissue paper and then packed carefully inside a c) Manufacturer’s name or recognized trade- strong cardboard carton box. The stand shall be mark and address. separately wrapped inacorrugated paper and shalIbe 8.2 Each of the four dew gauges shall berespectively packed inside awooden box. Both the packages shall numbered: beplaced inanother strong cardboard carton box. The packing shall be such that it shall safely withstand No. 1 – 5 cm; No. 2 – 25 cm; normal transit risks, Alternately, the instrument shall No. 3 – 50 cm; be packed asagreed to between the suppliers and the No.4 – 100 cm; and purchaser. 3 I I S 1 5 2 5 Ino 3:2 0 0 — 2 uO )* 1 u ) I t 4 l- - z 10. .0 N0 .$+ N0 t It t — —1-r--- .-L---- - — ------- - = m m0 I1 1S 15253:2002 I R55 = IR OF CLAMP 10’ 10: 15 15 010’10 T T 110 1 T * 1’ 180 I CLAMP BuSH _ TUBE 060 THICK 5.5 I-J=--l Alldimensions in millimetres. FIG, 4 DEW GAUGE — STAND WITH BASE AND CLAMP 5 1’