ICS 13.140  
 
Reference number  
DRS 236: 20 20 
© RSB 2020 
  
 RWANDA 
STANDARD  DRS 
236 
 
Second  edition  
2020-mm-dd 
Reaffirmed yyyy) 
Acoustics  — Noise Pollution  —Toler ance 
limit 
   
DRS 236: 20 20 
©RSB 20 20- 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  
 
 
 
 
 
 
 
 
© RSB2020 
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 thi s 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 236: 20 20 
iii                ©RSB20 20- All rights reserved  
 Contents  Page 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Criteria for noise  ................................ ................................ ................................ ................................ .... 2 
5 Tolerance limits for noise  ................................ ................................ ................................ .....................  2 
6 Occupational health and safety  ................................ ................................ ................................ ...........  4 
7 Noise and town planning  ................................ ................................ ................................ ......................  4 
8 Industrial noise  ................................ ................................ ................................ ................................ ...... 4 
 DRS 236: 20 20 
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 Foreword  
Rwanda Standard sareprepared by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Ann ex 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.  
RS 236 was prepared by Technical Committee RSB/TC 41, Environment Protection . 
In the preparation of this standard, reference was made to the following standard  (s): 
1) MS 175: Burnt Clay bricks – Code of practice for moulding and firing  
2) RS 117 :2014. Mining and quarrying  –Code of practice  
3) MS 173: Acoustics — Noise Pollution — Tolerance  limits  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This second  edition cancels and replaces the first (RS  236:2014) been technically revised.  
Committee membership  
The following organizations were represented on the Technical Committee on Environment Protection  
(RSB/TC 41) in the preparation of this standard.  
Appropriate  Community Sanitation & Energy Service international (ACSE -1) 
Biofuel Rwanda  
Compagnie pour l’environnement et le Développement ( COPED)  
Energy  W ater and Sanitation Authority ( EWASA  
Kanombe Military Hospital  
Kinazi cassava plant  
King Faisal Hospital  
Peat Energy Group  DRS 236: 20 20 
v                ©RSB20 20- All rights reserved  
 Resources effiecient and cleaner Production Center (RECP)  
Rwanda Environnent Management Company (RWEMACO)  
Rwanda Environment Man agement Authority (REMA)   
Rwanda Utility Regulatory Authority   
Sulfo Industries  
UMUTARA Polytechnic  
University of Rwanda - College of Arts and Social Sciences (UR -CASS)  
 University of Rwanda - College of Science and Technology (UR -CST)          
Rwanda Transport and Development Agency (RTDA)  - co-secretariat                                 
Rwanda  Standards Board  (RSB) – Secretariat  DRS 236: 20 20 
©RSB 20 20- All rights reserved                  vi 
 Introduction  
Acoustics are fundamentally important to learning environment . It is intrinsically linked with communication 
and aural communication.  
The source of outdoor noise worldwide is mainly caused by machines, transport, and propagation 
systems .Some of the main sources of noise in residential areas include loud music , transportation  (traffic, rail, 
airplanes, etc), lawn care maintenance, construction , electrical generators, explosions, and people . 
To be practical use any method of description, measurement, and assessment of environmental noi seis 
intended to be related in some way to what is known about human response to noise .Many adverse 
consequences of environmental noise increase with increasing noise but the precise dose -response 
relationships involved contin ue to be the subject of scientific debate.  
Noise pollution affects both health and behaviour. Unwanted sound (noise) can damage physiological 
healt h.Noise pollution can cause hype rtension , high stress levels, tinnitus , hearing loss, sleep 
disturbancesand other harmful and disturbing effects . High noise levels can contribute to cardiovascular  
effects in humans and an increased incidence of coronary artery disease  
There is a need to or miti gate the noise to reduce noise pollution  or to reduce the impact of that noise, whether 
outdoors or indoors . Multiple techniques have been developed to address interior sound  levels, many of which 
are encouraged by local building codes  
This standard aims at guiding concerned engineers companies or individual on how to control or mitigate the 
noise pollution among residential commercials, industrial, silent zone areas and other public buildings.  
 
 DRS 236: 2020  
1                ©RSB20 20- All rights reserved  
 Acoustics  — Noise  Pollution  —  Tolera nce limits  
1 Scope  
This Draft Rwanda Standard prescribes maximum allowable noise limits in industrial, commercial, residential 
and silence zone areas in respect to human beings. It also lay down sound level requirements for indoors of 
non-industrial  buildings.  
2 Normative references  
There are no normative references in this document  
3 Terms and definitions  
For the purposes of this standard, the following terms and definitions apply.  
3.1 
decibel (dB) one tenth of a bel  
decibel is the fundamental division of a logarithmic scale used to express the ratio of two specified or implied 
quantities, the number of bels denoting such a ratio being the logarithm to the base of 10 of this ration . 
3.2 
acoustics  
the science concerned the production, control, transmission, reception of sounds effects.  
3.3 
day time  
6 a.m. to 9 p.m.  
3.3 
night time  
9 p.m. to 6 a.m.  
3.4 
silence zone  
areas up to 100 m around such premises as hospitals, educational, institution, libraries a nd courts   
©RSB 20 20- All rights reserved                  2 
 3.5 
threshold of audibility  
zero decibel 
3.5 
Noise pollution  
is a regularly exposure to elevated sound levels  that may  lead to adverse effects in humans or other living 
organisms.  
3.6 
Environment noise  
is an accumulation of noise pollution that occurs outside  
4 Criteria for noise  
4.1 In selecting criteria to evaluate a situation, it is important to recognize various problems that may be 
caused by the noise. Criterion for environmental noise is the best deve lopment basing on problems faced by 
human beings, physical damage to structure and reduces utility of property.  
4.2 Noise has effects on health as specified in 4.2.1 - 4.2.4.  
4.2.1  Physical injury; exposure to sound pressure levels exceeding 140 dB, even for short period involves  a 
risk of morphological damage to the ear;  
4.2.2  Hearing loss; long term occupational exposure to high level noise greater than 70 dB can result in a  
gradual loss of hearing;  
4.2.3  Non-specific health effects; noise also results into physiological reactions such as; changes in 
heartrate, blood pressure and peripheral reactions and vestibular reactions. Many of these noise -induced 
reactionsare non -specific and are usually referred to as stress reactions; and 
4.2.4  Interference effects; these include; sleep interference, communication interference, and task  
performance.  
5 Tolerance limits for noise  
5.1 The categorization and tolerance limits for noise as specified in table 1 and table 2 i s recommended.  
Table 1—Noise level  
S/N Area code  Category of area  Limit in dB, Max  
Day time  Night time  DRS 236: 2020  
3                ©RSB20 20- All rights reserved  
 1 A Industrial area  75 70 
2 B Commercial area  65 55 
3 C Residential area  55 45 
4 D Silence zone  50 40 
 
Table 2—Maximum acceptable noise levels inside buildings  
S/No  Type of building  Maximum acceptable noise levels 
(dB )  
1 Offices  50-60 
2 Dwellings ( houses & flats)  45-55 
3 Schools ( class rooms  45-50 
4 Hospitals  40-50 
5 Churches or mosques  40-50 
5.2 The silence zones should be declared by a competent authority. Use of vehicle horns, and speakers 
and bursting or cracking shall be banned in these zones.  
5.3 The maximum recommended noise dose and exposure levels as specified in table 3 should be 
observed.  
Table 3—Allowable exposure duration  
1 sound  level (dBA)  Maximum exposure duration per day  
2 85 8h 
3 88 4h 
4 91 2h 
5 94 1h 
6 97 30 min  
7 100 15 min  
8 103 7.5 min  
9 106 3.7 min  
10 109 118 sec  
11 112 94 sec 
12 115 28 sec  
13 118 14 sec  
14 121 7 sec  
15 124 3 sec  
16 127 1 sec  
17 130-140 Less than 1 sec   
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 18 140  No exposure  
6 Occupational health and safety  
 6.1 No person shall be exposed to sound levels exceeding:  
a)  70 dB of continuous levels in any one way  
b) 85 dB of reasonably constant level for 8 h continuously in any one day;  
c) 135 dB as measured with an instrument set as ‘fast’ in any one day; and  
d) 150 dB in case of impulse as measured with an instrument set at ‘fast’ in any day  
6.2 If exposure is for periods longer than  eight hours, or if the sound level is fluctuating, an equivalent 
sound level shall be calculated, and this resultant noise shall not exceed the equivalent 85 dB. . 
6.3 All areas where people may be exposed to sound levels exceeding the limits specified in Table 3 shall 
be identified as ear protection areas and shall be suitably condoned off.  
7 Noise and town planning  
7.1  residential areas shall be set off from various roads according to average noise level that may emanate 
from them at any time. It is difficult to reduce out door noises coming into building. Therefore, it is advisable 
that during town layout planning (even planning of a suburb) the location of residential buildings, in particular 
be so arranged that they are far away from traffic, industrial, noisy surrounding s. 
7.2  Residential buildings situated on roads carrying heavy traffic should need similarly to be off from the 
road adequately and suitably oriented to attenuate the noise to required degree.  
8 Industrial noise  
Attention should be given to them during zoning to protect people from unnecessary noise  
 DRS 236: 2020  
 
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