Table Of Contentइंटरनेट 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
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1
5
2
5
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.0 N0 .$+ N0
t It t
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—1-r--- .-L---- - — -------
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=
m
m0
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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’
