ICS 13.220.40  
 
Reference number  
DRS 186 -1: 2023  
© RSB 2023  
  
 RWANDA 
STANDARD  DRS 
186-1  
 
Third  edition  
2023-mm-dd 
 
Fire safety for buildings — Code of 
practice  — 
Part 1: General principles of fire grading 
and classification  
   
DRS 186 -1: 2023  
©RSB 2023  - 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 2023  
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 186 -1: 2023  
iii                ©RSB 2023  - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Fire load  ................................ ................................ ................................ ................................ .........  3 
5 Classification of buildings  ................................ ................................ ................................ ...........  3 
5.1 Classification by occupancy  ................................ ................................ ................................ ....... 3 
5.2 Classification by fire resistance  ................................ ................................ ...............................  10 
6 Fire zones  ................................ ................................ ................................ ................................ .... 10 
6.1 Demarcation  ................................ ................................ ................................ ................................  10 
6.2 Number and designation of fire zones  ................................ ................................ .....................  10 
6.3 Changes in the fire zone boundaries  ................................ ................................ .......................  11 
6.4 Overlapping fire zones  ................................ ................................ ................................ ...............  11 
6.5 Temporary buildings  ................................ ................................ ................................ ..................  11 
 DRS 186 -1: 2023  
©RSB 2023  - All rights reserved                  iv 
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by Rwanda 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.  
WDRS 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 practice for Fire Safety of Buildings (General): General Principles of Fire Grading and 
Classification  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This third edition cancels and replaces the second edition (RS  186-1: 2018), clause  3, Table 1  which [has / 
have] been technically revised.  
DRS 186 consists of the following parts, under the general title Fire safety for buildings ― Code of practice : 
⎯ Part 1: General principles of fire grading and classification  
⎯ Part 2: Details of construction  
⎯ Part 3: Fire safety in p ublic buildings  
⎯ Part 4: Selection, installation and maintenance of automatic fire detection and alarm system  
⎯ Part 5: Exit requirements and personal hazard  
Committee membership  
The following organizations were represented on the Technical Committee of Fire safety  (RSB/TC 28) in the 
preparation of this standard.  
Bank of Kigali (BK)  
City of Kigali  
CrossTech 
Institution  of Engineers Rwanda (IER)  DRS 186 -1: 2023  
v                ©RSB 2023  - All rights reserved  
 Ministry of Infrastructure (MININFRA)  
PRIME  Insurance  Ltd 
Rwanda Defen ce Force (RDF)  
Rwanda Energy Group (REG)  
Rwand a Environment Management Authority (REMA) 
Rwanda Housing Authority (RHA)  
Rwanda National Police (RNP)  
Rwanda Social Security Board (RSSB)  
Sanlam  
Société Rwandaise d’Assurance (SONARWA)  
University of Rwanda - College of Science and Technology  (UR - CST)  
Rwanda Standards Board (RSB) – Secretariat  
 DRS 186 -1: 2023  
1                ©RSB 2023  - All rights reserved  
 Fire safety of buildings — Code of practice — Part 1: General principles 
of fire grading and classification  
1 Scope  
This Draft Rwanda Standard covers the general principles for fire grading /types  and classification of buildings 
according to the use or the character of occupancy.  
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  cited applies. For undated references, the 
latest edition of the referenced document (including any amendments) applies.  
RS ISO  13943, Fire safety — Vocabulary  
RS ISO  23932 -1, Fire safety engineering — General principles — Part 1: General  
3 Terms and definitions  
For the purposes of this standard, 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 environment  
Note 1 to entry : This includes floors, walls, beams, columns, doors, roof, 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 or task  
3.3 
load-bearing element  
building element that is designed to resist mechanical /seismic  forces   
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 3.4 
mechanical actions /seismic  forces  
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  
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 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  areas, 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 given 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 within the enclosure.  
3.10 
public  building  
building intended to be used by many people because of various activities carried out therein  DRS 186 -1: 2023  
3                ©RSB 2023  - All rights reserved  
 3.11 
flammable material  
solid, liquids or gases that can burn easily and harm people, other than living organisms, property or the 
environment  
3.12 
fire load   
amount of heat in kilocalories which is liberated per square meter of floor area of a compartment by the 
combustion of the contents of the building itself  
4 Fire load 
4.1 Amount of heat should be used as the basis for classification of occupancies.  
4.2 The fire load should be determined by multiplying the weight of all combustible materials by their calorific 
value and dividing the figure by the floor area under consideration.  
4.3 Different materials having the same weight and 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 ign ited 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.  
4.4 The content of a building is 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 r epresentation of the actual conditions, and the 
resulting effects on the structure immediately surrounding would be out of all proportion to these expected on 
the basis of average fire load.  
5 Classification of buildings  
5.1 Classification by occupancy  
5.1.1 All buildings should be classified, according to the use or the character of occupancy in one of the 
following groups and shall be described as per Table 1.   
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 of 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,  
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 exhibition  halls, museums, gymnasiums, 
restaurants, 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 and 
indoor sport  
 Occupancy where persons gather for the 
viewing of theatrical, operatic, orchestral, 
choral, cinematographically or sport 
performance  
A-3 - Places of 
instruction  Occupancy 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 events  
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 
similar purposes, Professional 
establishment and services (architects, 
attorneys, dentists, physicians, 
engineers, etc.); Radio and tele vision 
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 DRS 186 -1: 2023  
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 cause combustion with moderate rapidity 
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 
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 
Institutions  
 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 poisonous 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 rapidity 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 moderate risk category. 
This shall include any building in which 
the contents are of such comparative low 
combust ibility 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,  
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 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.  
H- HIGH -HAZARD 
(HEALTH )  High-hazard Group H occupancy 
includes, among others, the use of a 
building or structure, or a portion thereof, 
that involves the manufacturing, 
processing, generation or storage of 
materials that constitute a physical 
or health hazard  in quantities .  
High-Hazard (Group H) - places 
involving production or storage of very 
flammable or toxic materials. Includes 
places handling explosives and/or highly 
toxic materials (such 
as fireworks , hydrogen peroxide , 
and cyanide ). 
I- INSTITUTIONAL   Places where people are physically 
unable to leave without assistance. 
Examples: hospitals, nursing homes, and 
prisons.  
 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 
250 m2 
 M-2-Small shops  
 Occupancy where merchandise is 
displayed and offered for sale to the 
public and where the floor area does not 
exceed 250 m2 DRS 186 -1: 2023  
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  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: houses, 
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 under the same 
management, in which separate sleeping 
accommodation is provided on transient 
or permanent basis, with or without 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 m anagement, 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 consisting 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   These 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, storehouses, 
hangers and stables.   
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  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 risk 
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  
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 specific areas. An example of 
this is a shopping mall with apartments on 
the upper floors. The shoppi ng 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 buildings 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 nee d 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 DRS 186 -1: 2023  
9                ©RSB 2023  - All rights reserved  
 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 -separated 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 
separate fire areas, and each fire area is 
required to comply wi th the code based 
on the occupancy classification of that 
portion of the building.  
MISC - MISCELLANEOUS  
UTILITY   Buildings and structures of an accessory 
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  
 
5.1.2 Minor occupancy  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.  
5.1.3 Any building not covered by the above groups should be classified in the group which most nearly 
resembles its exiting or proposed use.  
5.1.4 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 requirements of this standard  for the new 
group or its subdivision  
5.1.5 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 for the new group or its 
subdivision   
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 5.2 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 provided below:  
a) Types I and II: Types of 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 combusti ble 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.  
6 Fire zones  
6.1 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’.  
6.2 Number and designation of fire zones  
6.2.1 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 development of the c ity or area. In large cities on areas, three fire zones may be 
necessary, while in smaller ones, one or two may be adequate.  
6.2.2 The fire zones should be made use of in land use development plan and should be designated as 
follows:   
a) Fire Zone No 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 occupancies.  
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.  DRS 186 -1: 2023  
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 6.3 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.  
6.4 Overlapping fire zones  
6.4.1 Any building 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.   
6.4.2 Any building so situated that it extends equally to more than one fire zone, it should be deemed to be 
situated in the fire zone having more hazardous occupancy  buildings.   
6.5 Temporary buildings  
6.5.1 Temporary buildings should be permitted only in Fire Zone No.1 and Fire Zone No.2 as the case may 
be, according to the purpose 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 Fire Zone No. 3 
6.5.2 Buildings stated in 5.5.1 should be completely removed on the expiry of the period specified in the 
permit.  
6.5.3 The following r estriction on type of construction  for new buildings should apply:  
a) Buildings erected in Fire Zone No.1 should 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 ; and  
c) Buildings erected in Fire Zone No. 3 should conform to construction of Type 1 or 2.  
 DRS 186 -1: 2023  
 
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