ICS  65.060.01  
 
Reference number  
DRS 271: 2015  
© RSB 2021  
  
 RWANDA 
STANDARD  DRS  
271 
First e dition  
2015-05-08 
Reaffirmed 2021-mm-dd 
Sprinkler head -rotating impact driven type 
— Test methods  
 
   
DRS 271: 2015  
©RSB 2021 - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2021 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw   DRS 271: 2015  
iii                ©RSB 2021 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 General conditions for test and inspection  ................................ ................................ ...............  2 
4.1 Sprinkler head on test  ................................ ................................ ................................ ..................  2 
4.2 Role of the manufacturer/dealer  ................................ ................................ ................................ . 2 
4.3 Site conditions and test equipment  ................................ ................................ ............................  2 
4.3.1  Sprinkler site  ................................ ................................ ................................ ................................ . 2 
4.3.2  Sprinkler mounting  ................................ ................................ ................................ .......................  2 
4.3.3  Collector description and location  ................................ ................................ .............................  3 
4.3.4  Wind measuring equipment and location for outdoor tests  ................................ ....................  3 
5 Test and inspection  ................................ ................................ ................................ ......................  4 
5.1 Verifica tion of the manufacturer’s technical data and information  ................................ ........  4 
5.2 Field performance test  ................................ ................................ ................................ .................  4 
5.3 Discharge capacity determination  ................................ ................................ ..............................  4 
5.4 Radius of throw determination and sprinkler’s speed of rotation  ................................ ..........  5 
5.5 Distribution pattern  ................................ ................................ ................................ ......................  5 
6 Test report  ................................ ................................ ................................ ................................ ..... 6 
Annex  A (normative)  Inspection sheet for sprinkler head  ................................ ................................ ... 7 
Annex  B (normative)  Field performance test data sheet  ................................ ................................ ...... 9 
B.1 Sprinkler head on test  ................................ ................................ ................................ ..................  9 
B.2 Test conditions  ................................ ................................ ................................ .............................  9 
B.3 Discharge capacity, sprinkler’s speed of rotation and radius of throw  ................................ . 9 
Table B.1 — Measurement values  ................................ ................................ ................................ ...........  9 
B.4 Sprinkler distribution test data sheet  ................................ ................................ .......................  10 
 DRS 271: 2015  
©RSB 2021 - All rights reserved                  iv 
 Foreword   
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards adopted 
by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS  271 was prepared by Technical Committee RSB/TC 023, Road vehicles . 
In the preparation of this standard, reference was made to the following standard:  
PAES 12 6: 200 2, Agricultural Machinery — Rotating Sprinkler head — Methods of Test  
The first edition (RS  271: 2015 ) has been re affirmed  by the Board on dd-mm-2021 . 
Committee  membership  
The following organizations were represented on the Technical Committee on Road vehicles  (RSB/TC 023) in 
the preparation of this standard.  
ATECAR  
KENSRIN COMPANY Ltd  
MOTA ENGIL  
PASCAL Technology Ltd  
PURE PRO Ltd  
Rwanda Polytechnic/ Integrated Polytechnic Regional College Ngoma (IPRC Ngoma)  
Rwanda Polytechnic / Integrated Polytechnic Regional College Kigali (RP/IPRC Kigali)  
University of Rwanda/ College of Science and Technology (UR -CST)  
VW Rwanda Ltd  
Rwanda  Standards Board  (RSB) – Secretariat  
 DRS 271: 2015  
1                ©RSB 2021 - All rights reserved  
 Sprinkler head -rotating impact driven type — Test methods  
 
1 Scope   
This Draft Rwanda Standard specifies the test and inspection methods for rotating sprinkler head  
It applies to verify the dimensions, weight and materials of construction of sprinkler head and to determine the 
performance of the device by measuring the discharge capacity, radius of throw and d istribution pattern at 
different base pressures.  
2 Normative references   
The following documents are referred to in the text in such a way that some or all of their content constitutes 
requirements of this document.  For dated references, only the edition cit ed applies. For undated references, the 
latest edition of the referenced document (including any amendments) applies.  
RS 241, Agricultural Machinery — Methods of sampling  
3 Terms and definitions   
For the purposes of this standard, the follow ing terms and def initions apply  
 3.1  
base pressure  
pressure measured at a point on the riser with a distance of at least five times the nominal sprinkler inlet diameter 
from the last upstream direction change or change in pipe cross sectional area  
3.2  
nozzle  
aperture  of the sprinkler through which the liquid is discharged  
3.3  
radius of throw  
farthest distance measured from the sprinkler head centreline to a point at which liquid is deposited  
3.4  
rotating sprinkler head  
rotating sprinkler device which by its rota ting motion around its vertical axis distributes liquid over an area   
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 4 General conditions for test and inspection  
4.1 Sprinkler head on test  
In the case of commercially manufactured sprinkler head, the sprinkler head submitted for test shall be taken 
from production model or series of production and shall be sampled in accordance with RS 241.  
4.2 Role of the manufacturer/dealer  
The manufacturer/dealer/client should comply with the test procedures of national testing authority.  
4.3 Site conditions and test equipmen t  
4.3.1  Sprinkler site  
4.3.1.1  The sprinkler shall be located in an area where the surface is smooth or where vegetative growth is less 
than 8 mm in height.   
4.3.1.2  Land shall have a maximum slope of 2 %. A map showing location and heights of windbreaks (tre es, 
shrubs, and other obstructions) shall be included on the test report.   
4.3.1.3  Tests shall not be run when these conditions are not satisfied.  
4.3.2  Sprinkler mounting  
4.3.2.1  The sprinkler nozzle height above the nearest col lector(s) for test purposes is  defined in Table 1.  
Table 1 — Sprinkler nozzle height above collectors  
Sprinkler type  Sprinkler inlet size (nominal pipe 
diameter)  Maximum nozzle height above 
collector  
Riser mounted; rotating  32 mm or smaller  915 mm  
Riser mounted; rotating  38 mm or larger  1830 mm  
Riser mounted; non -rotating  all 460 mm  
4.3.2.2  The sprinkler shall remain vertical (within 1 degree) throughout the duration of the test.  
4.3.2.3  The sprinkler riser shall be made from schedule 40 steel pipes. The riser nominal pipe size shall be the 
same size as the sprinkler inlet connection.   
4.3.2.4  The base pressure measurement location shall be defined as a point with a distance of at least five 
times the nominal sprinkler inlet diameter from the last upstream direction change or ch ange in pipe cross -
sectional area.  
4.3.2.5  The pressure tap shall be perpendicular to the riser and shall not extend into the inside diameter of the 
riser. Riser stream straightening vanes may be used when data are collected if such vanes are supplied as 
standard equipment with the sprinkler.  DRS 271: 2015  
3                ©RSB 2021 - All rights reserved  
 4.3.3  Collector description and location  
4.3.3.1  All collectors used to measure distribution shall be identical. They shall be such that the water does not 
splash out and such that evaporation is kept to a minimum.   
4.3.3.2  The type of collector shall be identified and recorded on the data sheet. If an evaporation suppressant 
is used, its type and method of application shall be identified and recorded on the data sheet.  
4.3.3.3  A square grid pattern of collectors sha ll be used, with the spacing between collectors being any whole 
number. The sprinkler shall be located in the cent re of a grid square (midway between 4 adjacent collectors).   
4.3.3.4  A minimum of 80 collectors shall be maintained such that the tops are le vel at all times. The maximum 
spacing of collectors for a predetermined radius of throw is shown in Table 2.  
Table 2 — Maximum spacing of collectors for predetermined sprinkler radius of throw  
Sprinkler radius of throw (m)  Maximum collectors spacing centre  to centre  (m  
˂ 3 0.30 
3 - 6 0.6 
6 – 12 0.75 
˃ 12 1.50 
4.3.3.5  The average above ground height of the tops of the 4 collectors near the sprinkler shall either be 0.9 m 
or 0.3 m above the ground.   
4.3.3.6  This measurement shall be reported  as collector height.   
4.3.3.7  Collectors shall be placed such that the vertical change in height between successive collectors shall 
not exceed a grade of 2 %.  
4.3.4  Wind measuring equipment and location for outdoor tests  
4.3.4.1  Wind velocity during the test period shall be determined with a rotating cup anemometer or device of 
equal or better accuracy.   
4.3.4.2  The wind direction shall be determined with a wind vane on the basis of 8 points of the compass (N, S, 
E, W, NE, NW, S E, SW).  
4.3.4.3  Wind velocity sensing equipment shall be located at a minimum height of 4 m.   
4.3.4.4  For sprinklers with trajectory height of more than 4 m, the sensor height shall be equal to the highest 
point of the main stream + 10 %.  
4.3.4.5  The wi nd sensing equipment shall be located outside the wetted area and at a location that is 
representative of the wind conditions at the sprinkler location.    
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 4.3.4.6  The maximum distance of the sensor location shall not exceed 45 m from the wetted area of the  sprinkler 
under test.  
5 Test and inspection  
5.1 Verification of the manufacturer’s technical data and information  
5.1.1  Inspection is carried out to verify the main dimensions, weight and materials of construction of sprinkler 
head in comparison with the lis t of manufacturer’s technical data and information.  
5.1.2  A plain and level surface shall be used as reference plane for verification of dimensional sprinkler head 
specifications.  
5.1.3  The items to be inspected and verified shall be recorded in Annex B.   
5.2 Field performance test  
5.2.1  The test is carried out to obtain the discharge capacity, speed of sprinkler rotation and radius of throw and 
sprinkler distribution pattern at base pressures ranging from 170 kPa up to 485 kPa at increments of 35 kPa.   
5.2.2 The base pressure shall not vary by more than 3 % during the test period.   
5.2.3  Pressure shall be measured and recorded at a point on the riser using pressure measuring devices 
accurate within + 3 % of the sprinkler test pressure.  
5.3 Discharge capacity determination  
5.3.1  The test shall be conducted by operating the sprinkler at base pressures indicated in 5.2.1.  
5.3.2  The discharge capacity shall be measured using volumetric method.   
5.3.3  The rotating sprinkler head is kept stationary by restraining  the impact arm from swinging. A hose is then 
connected to the sprinkler nozzle while a container is placed on the other end of the hose opening.   
5.3.4  The container shall have sufficient capacity to prevent the liquid from overflowing during measurement , 
and it shall be sufficiently rigid to prevent deformation when it is filled with liquid.   
5.3.5  The liquid shall be obtained in a container of known volume for a definite time usually one minute.  
5.3.6  The discharge capacity or sprinkler flow rate shall  be computed using the following formula:  
𝑄=𝑉
𝑡    
where DRS 271: 2015  
5                ©RSB 2021 - All rights reserved  
 𝑄  is the discharge, L/s ;   
𝑉 is the volume of liquid introduced into container in 𝑡 seconds ;  
𝑡  is the time required to introduce liquid of volume V, s .  
5.3.7  The flow through the sprinkler shall be measured to an accuracy of ± 3 % of the sprinkler flow rate.  
 
5.4 Radius of throw determination and sprinkler’s speed of rotation  
5.4.1  The test shall be conducted by operating the sprinkler at base pressures indicated in 5.2.1.  
5.4.2  The radius of  throw shall be taken by computing the average of two measurements (r1 and r2) made when 
the sprinkler base is rotated a quarter revolution (90°) about its axis (See Figure 1).   
 
Figure 1 — Measurement of radius of throw  
 
5.4.3  Three test trials shall be  conducted.  
5.4.4  The sprinkler’s speed of rotation shall be measured only while the sprinkler is rotating from its own drive 
mechanism.  
5.5 Distribution pattern  
5.5.1  The conditions for testing shall be in accordance with 4.3.  
5.5.2  The test shall be cond ucted by operating the sprinkler at base pressures indicated in 5.2.1.  
5.5.3  The depth of application in each collector shall be determined to an accuracy of + 2 % of the average 
application depth and recorded in a table showing the location of the collec tor relative to the sprinkler.  
5.5.4  Items to be measured shall be recorded in Annex C.  
 
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 6 Test report  
Test report shall include the following information:  
a) name of testing agency;  
b) test report number;  
c) title;  
d) summary;  
e) purpose  and scope of test;  
f) methods of test;  
g) table 1 — Machine specifications;  
h) table 2 — Field performance test data;  
i) observations; and  
j) name and signature of test engineer.  
 
 DRS 271: 2015  
7                ©RSB 2021 - All rights reserved  
 Annex  A 
(normative)  
 
Inspection sheet for sprinkler head  
Name of applicant:.. ..............................................  
Address:..........................................................  
Telephone No.:.................................................  
Name of distributor:..........................................  
Address:... ..................................................  
Name of Manufacturer:.................................  
Factory address:.........................................  
General information  
Brand:.........................................Model:............... .....................  
Type:.............................................  
Production date of sprinkler head to be tested (if available):............................................  
Table A.1 — Items to be inspected  
Items  Manufacturer’s specification  Verification by testing authority  
A.1 Dimensions and weight of the 
sprinkler    
A.1.1 Overall length, mm    
A.1.2 Overall width, mm    
A.1.3 Overall height, mm    
A.1.4 Weight, kg    
A.2 Specifications    
A.2.1 Sprinkler head    
A.2.1.1 Type    
A.2.2 Nozzle    
A.2.2.1 Type     
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 A.2.2.2 Size, mm    
A.2.2.3 Material    
A.2.2.4 Mode of attachment    
 
 
Figure A.1 — Measurement of length, width and height of sprinkler head  
 
 
DRS 271: 2015  
9                ©RSB 2021 - All rights reserved  
 Annex  B 
(normative)  
 
Field performance test data sheet  
B.1 Sprinkler head on test  
Brand.........................................  
Model:.............................................  
Date of test:........................................  
B.2 Test conditions  
Ambient temperature  
 Dry bulb, oC:..................................  
 Wet bulb, o C:...........................................  
Relative humidity, %:........................................  
Atmosphere pressure, mb:...............................  
Wind speed at 4 m elev., m/s:..................................  
B.3 Discharge capacity, sprin kler’s speed of rotation and radius of throw  
Table B.1 — Measurement values  
Base Pressure 
kPa Discharge capacity* L/s  Discharge capacity* L/s  Time for one 
rotation* s  
Nozzle 1  Nozzle 2 Total  300 mm riser  1000 mm riser   
170       
205       
240       
275       
310       
345       
380       
415        
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 450       
485       
*Average of three test trials  
B.4 Sprinkler distribution test data sheet  
B.4.1 Collector height:  ......................................................  
B.4.2 Collector entrance diameter:  .................................  
B.4.3 Sketch of test area:  ...........................................  
B.4.3.1 Location of sprinkler:  .........................  
B.4.3.2 Location of climatic measuring equipment:  ...........................  
B.4.3.3 Wind direction during test period:  ..............................  
B.4.3.4 Distance from sprinkler to all windbreaks (upwind, downwind, and to 
side):  .................................................................  
B.4.3.5 Heights of all windbreaks   
B.4.3.6 Map of sprinkler distribution pattern.......................................................................................DRS 271 : 2015  
 
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