Reference number  
DRS 186 -1: 201 8 
© RSB 2018 
  
 RWANDA 
STANDARD  DRS 
186-1 
 
Second  edition  
 
Code of practice for fire safety  
of building — 
Part 1:  
 
General principles of fire grading and 
classification  DRS 186-1:2018  
 
 
  DRS 186 -1: 201 8 
iii                 ©RSB 2018  All rights reserved  
 
 In order to match with technological development and to keep continuous progress in industr ies, 
Standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
 
 
 
 
© RSB 2018 
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  
Tel. +250 252 586103/582945  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  DRS 186 -1: 201 8 
©RBS 201 8 All rights reserved                  iv 
 
 Contents  Page  
Foreword  ................................ ................................ ................................ ................................ .............................. v 
1 Scope  ................................ ................................ ................................ ................................ ...................... 1 
2 Fire load  ................................ ................................ ................................ ................................ .................. 3 
3 Classification of building based on occupancy  ................................ ................................ ................. 3 
4 Description of classification groups ................................ .......................  Error! Bookmark not defined.  
4.1 Group A: Residential buildings  ................................ ...............................  Error! Bookmark not defined.  
4.2 Group B: Educational buildings  ................................ ..............................  Error! Bookmark not defined.  
4.3 Group C institutional buildings  ................................ ...............................  Error! Bookmark not defined.  
4.4 Group D assembly buildings  ................................ ................................ ... Error! Bookmark not defined.  
4.5 Grou p E business buildings  ................................ ................................ .... Error! Bookmark not defined.  
4.6 Group F mercantile buildings  ................................ ................................ .. Error! Bookmark not defined.  
4.7 Group FG industrial buildings  ................................ ................................ . Error! Bookmark not defined.  
4.8 Group H storage buildings  ................................ ................................ ...... Error! Bookmark not defined.  
4.9 Group J hazardous buildings  ................................ ................................ .. Error! Bookmark not defined.  
5 Fire zones  ................................ ................................ ................................ ................................ ............  10 
5.1 Demarcation  ................................ ................................ ................................ ................................ ........  10 
5.2 Number and designation of fire zones  ................................ ................................ .............................  10 
5.3 Changes in the fire zone boundaries  ................................ ................................ ................................  10 
5.4 Overlapping fire zones  ................................ ................................ ................................ .......................  10 
5.5 Temporary buildings  ................................ ................................ ................................ ..........................  11 
5.6 Restriction on  type of construction for new buildings  ................................ ................................ ... 11 
 DRS 186 -1: 201 8 
v                 ©RSB 2018  All rights reserved  
 
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RBS ) 
Board  of Directors in  accordance with the procedures of RSB, in complianc e 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 186-1 was prepared by Technical Committee RSB/TC 28, Fire safety . 
In the preparation of this standard, reference was made to the following standard:  
IS 1641:1988; Code of pra ctice for Fire Safety of Buildings (General): General Principles of Fire Grading and 
Classification  
The assistance delivered from the above source is hereby acknowledged with thanks.  
This second edition cancels and replaces the first edition (RS  186-1: 201 3) of which has been technically 
revised . 
DRS 186 consists of the following parts, under the general title Code of practice for fire safety of building : 
Part 1: General principles of fire grading and classification  
Part 2: Details of Construction  
Part 3: Fire Safety in public buildings  
Part 4: Selection, installation and maintenance of automatic fire detection and alarm system  
Part 5: Exit requ irements and personal hazard  DRS 186 -1: 201 8 
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Committee membership  
The following organizations were represented on the Technical Committee on Fire Safety (R SB/TC 28) in the  
preparation of this standard.  
City of Kigali  
College of Science and Technology  
CABLELINE  
Energy Ut ility Corporation Limited  
ELECTRICOM  
ISCO  
Institute of Engineers Rwanda  
Ministry of Disaster Management and Refugees  
Ministry of Infrastructure  
Rwanda Housing Authority (RHA)  
Rwanda Motor Ltd  
Rwanda National Police  
REAL  
Société Rwandaise d’Assurance (SONAR WA)  
SONATUBES  
Rwanda Standards Board (RSB) - Secretariat  DRS 186 -1: 201 8 
vii                 ©RSB 2018  All rights reserved  
 
 DRS 186 -1: 201 8 
1                 ©RSB 2018  All rights reserved  
 
 Code of practice for fire safety of building  — Part 1: General principles of 
grading and classification  
1 Scope  
This standard covers the general principles of fire grading of buildings and classific ation according to the use 
or the character of occupancy . 
2 Terms and definitions  
For the purposes of this document, the terms and definitions given in RS ISO 13943,  RS ISO 23932 and the 
following apply.  
3.1 
building element  
integral part of a built environm ent 
Note 1 to entry:  This includes floors, walls, beams, columns, doors, and penetrations, but does not include 
contents.  
3.2 
function  
role and actions assigned to, or required or expected of, various parts of a structure to achieve a specified 
objective o r task  
3.3 
load-bearing element  
building element that is designed to resist mechanical actions  
3.4 
mechanical actions  
defined force impacts on other elements due to strain or stress redistribution within a structure, or part of a 
structure, in fire  
3.5 
non-load-bearing element   
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 building element that is not designed to resist mechanical actions besides its own weight  
3.6 
reliability  
ability of a structure or structural element to fulfil the specific requirements, including working life, for which it 
has been designed  
3.7 
structure  
assembly of materials forming a construction for occupancy or use to serve a specific purpose  
Note 1 to entry:  This includes, but is not limited to, buildings, open platforms, bridges, roof assemblies over 
open storage or process are as, tents, air -supported structures, and grand stands.  
3.8 
structural fire performance  
extent to which a structure or structural element fulfils the specific requirements, including working life, for 
which it has been designed, when exposed to fire for a g iven time  
3.9 
thermal actions  
description of the variation of temperatures or heat fluxes as a function of time in an enclosure  
Note 1 to entry:  These temperatures or heat fluxes depend on fire load density, fuel arrangement, geometry of 
and openings withi n the enclosure.  
3.10 
Public building  
Building intended to be used by many people because of varoiuous activities carried out therein  
3.11 
Flammable material  
Solid, liquids or gases that can burn easily and harm people, other than living organisms, propert y or the 
environment  DRS 186 -1: 201 8 
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3 Fire load;  
2.1 Fire load is the amount of heat in kilocalories which is liberated per square meter of floor area of a 
compartment by the combustion of the c ontents of the building itself.  This amount of heat is used as the basis 
for classification of occupancies.  
2.2 The fire load is determined by multiplying the weight of all combustible materials by their calorific value 
and dividing the figure by the floor area under consideration.  
2.3 Different materials having the same weight an d same calorific value may present different hazards on 
account of their other properties, such as ease of ignition; speed of burning, and liberation of heat and fumes. 
Thus, some materials are more readily ignited than other, again, some burn more rapidly  than others, some 
materials when heated on fire liberate dangerous fumes, and some may readily cause ignition of other 
materials.  
2.4 The content of a building are rarely distributed uniformly over the whole floor area. From the fire 
protection point, it would be undesirable to have all combustible material concentrated on a fraction of the floor 
area, as the average taken over the whole area would not give a true representation of the actual conditions, 
and the resulting effects on the structure immediate ly surrounding would be out of all proportion to these 
expected on the basis of average fire load.  
4 Classification of building s  
4.1 Classification by occupancy  
All buildings should be classified, according to the use or the character of occupancy in one of th e following 
groups and shall be described as in table below :   
Table 1 -Use and occupancy classification  
Group  Classification  Sub Group  Description  
A ASSEMBLY  A-1, A-2, A-3, A- 
4 ,A-5  
 These shall include any building or part 
of a building, where number o f persons  
not less than 50 congregate or gather for 
amusement, recreation, social, religious, 
patriotic, civil, travel and similar 
purposes, for example, theatres, motion 
picture houses, assembly halls, 
auditoria, exhibition  halls, museums, 
gymnasiums, res taurants, places of 
worship, dance halls, club rooms, 
passenger stations and airports, surface 
and marine public transportation 
services, recreation piers and stadia, 
etc. 
A-1 - Entertainment 
and public  
assembly  
 Occupancy where persons gather to eat, 
drink, dance or participation other 
recreation  
A-2 - Theatrical Occupancy where persons gather for the  
©RBS 201 8 All rights reserved                  4 
 
 and indoor sport  
 viewing of theatrical, operatic, orchestral, 
choral, cinematographically or sport 
performance  
A-3 - Places of 
instruction  
 Occup ancy where school children, 
students or other persons assemble for 
the purpose of tuition or learning  
A-4 - Worship;  Occupancy where persons assemble for 
the purpose of worshipping  
A-5 - Outdoor 
sport;  Occupancy where persons view outdoor 
sports ev ents 
B – BUSINESS  
(COMMERCE)   Occupancy where transaction of 
business of non -industrial process is 
carried out. Example of use of the 
building or structure, or a portion may 
include; - office, professional or service -
type transactions, including storage of  
records and accounts, airport traffic 
control towers, Banks; Civic 
administration; Clinic — outpatient; 
Electronic data processing; 
Laboratories —testing and research; 
Motor vehicle showrooms; Post offices; 
Print shops; keeping of accounts and 
records and s imilar purposes, 
Professional establishment and services 
(architects, attorneys, dentists, 
physicians, engineers, etc.); Radio and 
television stations;  
Telephone exchanges; Training and skill 
development not within a school or  
academic program.  
B 1 - High risk 
commercial service  
 Occupancy where a non -industrial 
process is carried out and where either 
the material handled or the process 
carried out is liable, in the event of fire, 
to cause combustion with extreme 
rapidity or give rise to poisonous fumes, 
or cause explosions  
B 2- Moderate risk 
commercial  
service  
 Occupancy where a non -industrial 
process is carried out and where either 
the material handled or the process 
carried out is liable, in the event of fire, 
to cause combustion with moderate 
rapidi ty but is not likely to give rise to 
poisonous fumes, or cause explosions  
B 3 - Low risk 
commercial 
service.  
 Occupancy where a non -industrial 
process is carried out and where neither 
the material handled nor the process 
carried out falls into the high or 
moderate risk category  
 E- EDUCATIONAL   Places of instruction Occupancy where 
school children, students or other 
persons assemble for the purpose of DRS 186 -1: 201 8 
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 tutoring or learning. These shall include 
any building used for school, college, 
and other training  institutions for day -
care purposes  
  E 1 – Up to Senior 
Secondary level.  
 This sub -division shall include any 
building or a group of buildings under 
single management, which is used for 
students not less than 20 in number  
  E 2 - All 
others/training 
Instit utions  
 This sub -division shall include any 
building or a group of buildings under 
single management that is used for 
students not less than 100 in number  
 F-FACTORY AND  
INDUSTRIAL   Places where goods are manufactured 
or repaired (unless considered "High - 
Hazard"  
  F- 1 - High risk 
industrial  
 
 Occupancy where an industrial process 
is carried out and where either the  
material handled or the process carried 
out is liable, in the event of fire, to cause 
combustion with extreme rapidity or give 
rise to pois onous fumes, or cause 
explosions  
  F -2 - Moderate risk 
industrial  
 Occupancy where an industrial process 
is carried out and where either the  
material handled or the process carried 
out is liable, in the event of fire, to cause 
combustion with moderate ra pidity but is 
not likely to give rise to poisonous 
fumes, or cause explosions  
  F- 3 - Low risk 
industrial  
 Occupancy where an industrial process 
is carried out and where neither the  
material handled nor the process carried 
out falls into the high or mode rate risk 
category. This shall include any building 
in which the contents are of such 
comparative low combustibility and there 
are hardly any possibilities for any self 
propagating  
fire to occur and the only consequent 
danger to life and property may arise  
from panic, fumes or smoke, or fire from 
some external source  
  F- 4 - Plant room  
 Occupancy comprising usually 
unattended mechanical or electrical 
services  
necessary for the running of a building.  
 
 I- INSTITUTIONAL   Places where people are physically 
unable to leave without assistance. 
Examples:  
hospitals, nursing homes, and prisons.   
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   I- 1-Place of 
detention[ 
Restrained]  Occupancy where people are detained 
for punitive or corrective reasons or  
because of their mental condition  
  I -2- Hospitals and 
health centres  
[Incapacitated]  
 Occupancy where people are cared for 
or treated because of physical or mental 
disabilities and where they are generally 
bed ridden  
  I-3- Other 
Institutional  Occupancy where groups of people who 
either are not fully fit, or  who are  
restricted in their movements or their 
ability to make decisions, reside and  are 
cared for  
 M- MERCANTILE   These shall include any building or part 
of a building, which is used as shops, 
stores, market, for display and sale of 
merchandise, either  wholesale or retail.  
Mercantile buildings shall be further sub -
classed as follows:  
  M-1-Large shops  
 Occupancy where merchandise is 
displayed and offered for sale to the 
public and  
where the floor area exceeds 250m 2 
  M-2-Small shops  
 Occupancy where  merchandise is 
displayed and offered for sale to the 
public and  
where the floor area does not exceed 
250m 2 
  M-3-Wholesalers 
stores  
 Occupancy where goods are displayed 
and stored and where only a limited  
selected group of persons is present at 
any one time 
 R- RESIDENTIAL   These shall include any building in which 
sleeping accommodation is provided for 
normal residential purposes with or 
without cooking or dining or both 
facilities, except any building classified 
under I (Institutions); Examples: house s, 
apartment buildings, hotels, and motels. 
Residential - shall be further sub -classed  
as follows : 
  R-1-Hotel  Occupancy where persons rent 
furnished rooms, not being dwelling 
units.  
 
  R-2-Lodging  These shall include any building or 
group of buildings u nder the same  
management, in which separate 
sleeping accommodation is provided on 
transient  
or permanent basis, with or without DRS 186 -1: 201 8 
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 dining facilities but without cooking 
facilities  
for individuals is provided. This includes 
inns, clubs, motels and guest houses . 
  R-3-Dormitory  These shall include any building in which 
group sleeping accommodation is 
provided, with or without dining facilities 
for persons who are not members of the 
same family, in one room or a series of 
closely associated rooms under joint 
occupancy and single management, for 
example, school and college dormitories,  
students, and other hostels and military 
barracks.  
  R-4-Domestic 
residence  Occupancy consisting of two or more 
dwelling units on a single site  
  R-5-Dwelling house  
 Occupancy co nsisting of a dwelling unit 
on its own site. May include a garage 
and other domestic outbuildings, if any. 
It will usually be occupied by members 
of one or two families and has a total 
sleeping accommodation for not more 
than 
20 persons.  
 S- STORAGE   Thes e shall include any building or part 
of a building used primarily for the 
storage or sheltering including servicing, 
processing or repairs incidental to 
storage) of goods, ware or merchandise 
e.g. warehouses, cold storage, freight 
depots, transit sheds, st orehouses, 
hangers and stables.  
  S-1- High risk 
storage  
 Occupancy where material is stored and 
where the stored material is liable, in the 
event of a fire, to cause combustion with 
extreme rapidity or give rise to 
poisonous fumes, or cause explosions  
  S-2- Moderate risk 
storage  
 Occupancy where material is stored and 
where the stored material is liable, in the  
event of a fire, to cause combustion with 
extreme rapidity but is not likely to give  
rise to poisonous fumes, or cause 
explosions  
  S-3- Low ri sk 
storage  
 Occupancy where the stored material 
does not fall into the high or moderate 
risk 
category  
  S-4- Parking 
garage  Occupancy used for storing or parking of 
more than 10 motor vehicles  
 MEM - MEMORIAL   Sites or building erected for 
commemoration and honor of genocide 
victims   
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  MIX – MIXED USE   Many buildings may have multiple 
occupancies. These are referred to as 
"mixed occupancies" and the different 
parts will be required to meet the codes 
for those mspecific areas. An example of 
this is a shoppi ng mall with apartments 
on the  
upper floors. The shopping area itself is 
Group M (mercantile), while the  
apartments would qualify as Class R 
(Residential).  
  MIX-1- Accessory 
occupancy  The intent of the accessory occupancy 
provisions recognizes that build ings 
often  
have rooms or spaces different from but 
accessory to the main occupancy. The  
accessory occupancy provisions require 
that the space be accessory or ancillary 
to the main occupancy and that it does 
not exceed 10% of the area of the story 
in 
which it is located. The accessory 
occupancy does not need to be 
accounted for in  
construction type determination and 
related height/area determination for a  
building. The allowable building area and 
allowable building height are permitted  
to be based solely on the main 
occupancy classification(s).  
  MIX-2- Non- 
separated 
occupancy  
 The non -separated occupancy 
provisions allow multiple occupancies 
without a physical separation between 
them. Occupancies are individually 
classified in accordance with this code 
but are not subject to the 10% area limit 
applicable to accessory occupancies. 
The requirements of the code are based 
on the occupancy  
classification of the space, except that 
the most restrictive requirements for fire 
safety are applied to the total non -
sepa rated occupancy fire area . 
  MIX-3- Separated 
occupancies  
 The separated occupancy provisions 
require physical separation by fire barrier 
walls and/or horizontal assemblies with a 
fire-resistance rating between 
occupancies. Occupancies are located 
in sepa rate fire areas, and each fire area 
is 
required to comply with the code based 
on the occupancy classification of that  
portion of the building.  
 MISC -  Buildings and structures of an accessory DRS 186 -1: 201 8 
9                 ©RSB 2018  All rights reserved  
 
 MISCELLANEOUS  
UTILITY  character and miscellaneous structures  
not classified in any specific occupancy 
shall be constructed, equipped and  
maintained to conform to the 
requirements of this code commensurate 
with the  
fire and life hazard incidental to their 
occupancy. Examples: Agricultural  
buildings; Aircraft hangars, accessory to 
a one - or two -family residence; Barns; 
Carports; Fences more than 6 feet (1829 
mm) high; Grain silos, accessory to a  
residential occupancy; Greenhouses; 
Livestock shelters; Private garages;  
Retaining walls; Sheds; Stables; Tanks  
3.2 Minor occ upancy incidental to operations in another type of occupancy should be considered as part of 
the main occupancy and should be classified under the relevant group for the main occupancy.  
3.3 Any building not covered by the above groups  should be classified in the group which most nearly 
resembles its exiting or proposed use.  
3.4 Where change in the occupancy of any building places it in a different group or in a different subdivision 
of the same group, such building should be made to comply with the requirem ents of this standard for the new 
group or its subdivision  
3.5 Where the new occupancy of any building is less hazardous, based on life and fire risk than its existing 
occupancy, it should not be necessary to conform to the requirements of this standard fo r the new group or its 
subdivision  
4.2 Classification by fire resistance  
Buildings and structures erected or to be erected, altered or extended in  height or area shall be classified in  
one of the five construction types provide d  below  
a) Types I and II:  Types o f construction in which  the building elements are of non  combustible  materials . In 
this type of construction the building elements are of noncombustible materials  such as concrete and 
steel. The roof is also of noncombustible material such as  concrete or steel. 
b) Type III: type of construction in which the exterior  walls are of noncombustible materials and the interior 
building elements are of  any material. It has masonry bearing walls but the  floors, structural framework 
and roof are made of wood or other co mbustible  material.  
c) Type IV: Heavy Timber, HT is that type of construction in  which the exterior walls are of  noncombustible 
materials and the interior building  elements are of solid or laminated wood without concealed spaces.  
d) Type V: Type V - Wood -frame  construction is the most combustible of the five  building types. The interior 
framing and exterior walls may be wood. A wood  frame  building is the only one of the five types of 
construction that has  combustible exterior walls.   
©RBS 201 8 All rights reserved                  10 
 
 5 Fire zones  
5.1 Demarcation  
The city or area sho uld, for the purpose of this standard be demarcated into distinct zones, bases on fire 
hazard inherent in the buildings and structures according to occupancy  (see 4 ), which should be called the 
‘Fire Zone’.  
5.2 Number and designation of fire zones 
5.2.1  The number of fire zones in a city or area under the jurisdiction of the authority depends upon the 
existing layout, types of building construction classification of existing buildings based on occupancy (see 2) 
and the expected future developmen t of the city or area. In large cities on areas, three fire zones may be 
necessary, while in smaller ones, one or two may be adequate.  
5.2.2  The fire zones should be made use of in land use development plan and should be designated as 
follows:   
a) Fire Zone N o 1; this should comprise areas having residential (Group R), educational (Group E), 
institutional (Group I), assembly (Group A), small business (Sub -division B-3) and retail mercantile (Group 
M) buildings, or areas which are under development for such occ upancies.  
b) Fire Zone No.2 ; this should comprise business (Subdivisions B-2 and B-3) and industrial buildings 
(Subdivisions F-2 and F-3) except high hazard industrial buildings (Subdivision F-1) or areas which are 
under development for such occupancies.  
c) Fire Zone No.3 ; this should comprise areas having high hazard industrial buildings (Sub -division F-1), 
storage buildings (Group S) and buildings for hazardous uses or areas which are under development for 
such occupancies.  
5.3 Changes in the fire zone boundaries  
When the boundaries of any fire zone are changed, or when it is intended to include other areas or types of 
occupancies in any are a zone, it should be done by following the same procedure as per promulgating new 
rules.  
5.4 Overlapping fire zones  
5.4.1  Any build ing so situated that it extends to more than one fire zone, it should be deemed to be situated 
in the fire zone in which the major portion of the building or structure is situated.   
5.4.2  Any building so situated that it extends equally to more than one fi re zone, it should be deemed to be 
situated in the fire zone having more hazardous occupancy  buildings.   DRS 186 -1: 201 8 
11                 ©RSB 2018  All rights reserved  
 
 5.5 Temporary buildings  
5.5.1 Temporary buildings should be permitted only in Fire Zone No.1 and Fire Zone No. 2 as the  case may 
be, according to the purpos e for which these are to be used, by special permit from entrusted authority for a 
limited period and subject to such conditions as may be imposed in the permit.  More precaution should be 
taken while issuing special permit for the t emporary buildings in Fi re Zone No. 3 
5.5.2  Buildings stated in 5.5.1 should be completely removed on the expiry of the period specified in the 
permit. 5.5.3  The following r estriction on type of construction  for new buildings should apply:   
a) Buildings erected in Fire Zone No.1 shoul d conform to construction of Type 1, 2, 3 , 4. or 5 
b) Buildings erected in Fire Zone No.2 should conform to construction of Type 1, 2, or 3.  
c) Buildings erected in Fire Zone No. 3 should conform to construction of Type 1 or 2.   
 RS 186 -1: 2013  
ICS 13.220.40  
 
 
©RBS 2013  All right s reserved