KENYA STANDARD       DKS 2867: 2018  
                                                                                 ICS  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Occupational s afety and health —
demolition of buildings — code of 
practice   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
        © KEBS 201 8 First Edition , 2018 DKS 2867 : 2018  
 
© KEBS 2018 — All rights reserved  TECHNICAL COMMITTEE REPRES ENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Directorate of Occupational Safety and Health Services (DOSHS)  
Kenyatta National Hospital (KNH)  
Radiation Protection Board  
Kenya Medical Research Institute (KEMRI)  
Kenyatta University — Department of Environmental Health  
National Environmental Management Authority (NEMA)  
Ministry of Health — Department of Public Health  
Consumer Information Network  
East Africa association for radiation protection  
Kenya Bureau of Standards — Secretariat  
 
 
 
 
REVISION OF KENYA STANDARDS  
 
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for improvements to published standards, addressed to the Managing Director, Kenya Bureau o f Standards, 
are welcome.  
 
 
 
 
 
 
 
© Kenya Bureau of Standards, 201 8 
 
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001 of  the Laws of Kenya, copyright 
subsists in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bure au of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any mea ns without prior permission in writing 
from the Managing Director.  
  KENYA STANDARD                                         DKS 2867 : 2018  
                                                                                     ICS  
© KEBS 2018 — All rights reserved    iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
Occupational s afety and health  — demolition 
of buildings  — code of practice  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office: P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
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Fax: (+254  041) 229448    Fax: (+254 057) 21814  
 
  DKS 2867 : 2018  
 
© KEBS 2018 — All rights reserved   
Foreword  
 
This Kenya Standard has been prepared by the Sub -Technical Committee on Occupational Health and 
Safety under the guidance of the Standards Projects Committee, and it is in accordance with the procedures 
of the Kenya Bureau of Standards.  
 
During the preparation of this standard, reference was made to the following documents:  
 
ISO 45001:2018 - Occupational health and safety management systems — Requirements with guidance for 
use 
 
ISO 14123 -1:2015 Safety of machinery — Reduction of risks to health resulting from hazardous substances 
emitted by machinery — Part 1: Principles and Specifications for machinery manufacturers  
 
Acknowledgement is hereby made for the assistance received fro m these sources . 
 
  
KENYA STANDARD        DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    1 
 
 
 
 
 
 
 
  
Occupational s afety and health — demolition of buildings — 
code of practice   
 
1 Scope  and field of application  
 
1.1 Scope  
This standard lays down  safety and health requirements for carrying out safely the demolition/dismantling  
of all types of buildings, for example, residential building (load -bearing structure, multistoreyed framed 
structures) , public buildings and factories.  
 
1.2 Application  
This standard shall apply to personnel  engaged in manual or mechanical demolition/disman tling of all types 
of buildings.  
 
 
2 Normative references  
The following referenced documents are indispensable for the application of this Kenya Standard. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies.  
 
ISO 45001:2018 - Occupational health and safety management systems — Requirements with guidance for 
use 
 
ISO 14123 -1:2015 Safety of machinery — Reduction of risks to health resulting from hazardous substances 
emitted by machinery — Part 1: Principles and Sp ecifications for machinery manufacturers  
 
3 Terms and definitions   
For the purposes of this document, the following terms and definitions shall apply  
 
3.1  
personnel  
include workers, companies and contractors  involved in t he demolition work of buildings  
 
  
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  3.2  
workmen  
include both men and women workers  involved in the demolition of building  
 
3.3  
building owner  
person or organization having the right to refurbish, demolish o r partly demolish a building , by virtue of legal 
ownership or other legal authority  
 
3.4  
client  
initiator of the works for demolition  or partial demolition for structural  refurbishment . The client  is usually the 
structure owner, but could also be, for example , a main contractor.  
   
3.5  
competent person  
person with sufficient knowledge of the specific tasks to  be undertaken  and the risks which the work will 
entail, and with sufficient training, experience and ability to enable them to carry out  their duties in relation to 
the project, to recognize their limitations, and to take appropriate action to pre vent harm to those carrying out 
or affected by the work . 
  
3.6  
relevant  Authority  
organization designated as for demolition  of buildings,  disposal of the debris materials, and  include 
government regulatory authority  
3.7  
decommissioning  
process whereby an area  is brought from its fully operational status to one where all live or charged systems 
are rendered  dead or inert and reduced to the lowest possible hazard level . 
 
3.8 deliberate collapse   
controlled removal or weakening of key structural members causing colla pse in a planned way of  the whole 
or part of the building or structure being demolished or partially demolished . 
  
3.9 materials recycling   
action of reprocessing materials which have previously been proce ssed for inclusion in a product  
 
3.10 permit to  work procedure   
procedure which sets out  the agreed work to be undertaken  on identified  equipment, or in an identified  area, 
and the precautions to be taken  and to be managed as  part of a safe system  of work  
 
3.11 recovery   
operation the principal result of which  waste is serving a useful purpose by replacing other materials which 
would otherwise have been used to fulfil a  particular function, or waste being prepared to fulfil that  function, 
in the plant or in the wider economy   
 
3.12  
structural refurbishment  DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    3 alteration to an existing  retained building or structure that involves removal or modification of structural 
elements or members, which might or might not cause instability  
 
3.13  
waste  
substance or object which the holder discards or intends to discard or is r equired to discard  under the 
provisions of the national law  
 
3.14  
permit to work   
a written  notice, which sets out the work to be done, the hazards  involved and the precautions to be taken 
before the work commences in order to secu re the safety and health of the employee.  
 
4 Approaches to demolition  
 
4.1 Assessment of approaches  
 
On the basis  of the results of the options asses sment, one, or a combination of  the following approaches 
should be  selected.  
 
a) complete demolition with potential reuse of site  (possibly  by others).  
b) complete demolition and rebuild.  
c) partial demolition and building some new replacement facilities.  
d) structural refurbishment while  not in use.  
e) structural refurbishment while  in use.  
 
  
4.2 Intervention principles  
 
The extent and effect of any  particular planned process or physical  intervention should be  assessed  by a 
competent person.  A decision should be  taken about which activities would be most appropriate.  
 
When considering the activities and the possible methods to be  adopted, the various hazards and thus 
potential risks should be  assessed, for  example, where materials are  to be  removed and where structural 
instability might be  possible, whether planned or unplanned. The a mount of materials to be  removed is not 
necessarily the key criterion as the effect of their removal should be  considered together with the proposed 
methods of removal, including the structural instability that could be  caused. The need for  auxiliary ( or 
temporary) or permanent works to provide interim (or replacement permanent) support should be  assessed 
and, if necessary, planned. The design should ensure that the structure is taken down in a planned and 
controlled manner, thus avoiding any unplanned  structural instability or collapse.  
 
4.3 Selection of the  approach  
 
When selecting an  approach to demolition activities, a number of factors should be  taken into a ccount, 
including the following:  
 
a) the information given in relevant guidance documents;  
b) health, safety  and environmental requirements;  
c) the needs of the clien t, the users  and the workforce;   
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  d) the type, age, condition, use  and business activity (if appropriate) of the facility  and local  conditions 
and constraints (e.g.  access,  existing servi ces, party walls);  
e) the need to avoid disruption to business continuity, the community and nearby structures;  
f) legislative requirements ;   
g) party  wall  constraints;  
h) cost and commercial bene fits. 
 
4.4 Choosing the  methodology  
 
To ensure a successful outcom e, the following methodologies should be  adopt ed as may be appropriate.  
a)    h and working (manually).  
 
b)    mechanical working (machine use).  
 
c)    a combination of manual  and mechanical working.  
 
Decision to choose the appropriate methodology should take account of such  factors as sustainability, 
waste strategies, client issues,  risk management issues,  e.g.  increased risk of accident or injury,  the 
potential for  statutory nuisance, prohibition and prosecution, and insurance issues.  
 
Example:  
A buildi ng contains a large amount of “soft strip” material. If the building is detached and there is adequate 
space around the structure, the decision may  be taken to manually strip  out all of the material to assist  in a 
clean reduction of the remaining struct ure. However, if the same building is located in a heavily populated or 
dense area, such  as a city or town centre, the best option might be to reduce the structure with all materials 
in situ  and transport this  elsewhere for segregation and processing.  
 
4.5 Demolition activities in structural  refurbishment  
 
General  
 
Because demolition activities as part of structural refurbishment can  alter the load -bearing parts of the 
structure, the following issues  should be  assessed.  
a) the load -bearing requirements and the necessar y temporary support system.    
b) the potential for  unplanned collapse of structure (e.g.  often due to lack  of  understanding of traditional 
building construction).  
 
c) fire safety (e.g.  fire  loading, means of escape, protection).   
d) all services,  including electricity and gas  (e.g.  isolation and disconnection of services,  especially 
where properties either remain in occupation or are  the subject of phased handover, leading to work 
being carried out with live services).   
e) health issues  [e.g.  n oise and vibration, the presence of asbestos, lead, silica, polychlorinated 
biphenyls (PCBs) or zoonoses carriers, the need to provide welfare facilities].   
f) client  issues  (e.g.  raising awareness, wide variation of client experience, provision of relevant 
information).   
Competent advisors should be  involved early  in the process. When gathering information, the design 
team should identify and understand the concerns and needs of:   
 DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    5 i. the client;   
ii. the occupier of the building (who might not be  the c lient, but could be living  in the building 
while the work is done);   
iii. the contractor; and   
iv. any  third parties (e.g.  members of the public, adjoining owners, emergency services, 
environmental matters).   
The team should also  identify the need during the project for  emergency procedures in the event, for  
example, of fire,  power loss and security incidents.  
 
4.5.1  Extent  and effects of demolition activities in structural refurbishment   
The degree to which demolition in structural refurbishment might be  invasive and affect the structure 
should be  assessed b oth before and during the work.  This assessment should be  undertaken for  each 
element of work and then encompassed into the demolition plan.  
 
4.5.2  Types of work  involving partial structural  demolition and structural  supports  
  
The type of instability created in a structure should be  assessed before and after such  work as the 
following is carried out:  
a) removal of floors;  
b) removal of walls;  
c) chimney breast/stack removal;   
d) alterations to t raditional building structures;  
e) forming new openings ; 
f) excavation/removal of foundations, etc.,  for  basement construction under existing buildings and 
garden areas ; 
g) loft conversions;  
h) facade retention ; 
i) cutting back  floors to upgrade insulation/create mezzanine/two storey height areas in the building 
interior ; 
j) extensions;  
k) construction of additional floors at ro of level  of existing buildings;  
l) conversion of office buildings into residential/hotel accommodation ; 
m) structural refurbishment, such  as:  
i. modernization, e.g.  upgrading a facility  where the same use  is to be retained;  
 
ii. change of use,  including subdivision; and  
 
iii. significant rebuild, e.g.  undertaking major structural works but reusing the existing 
foundations and retaining the facade.  
 
NOTE : Activities not gen erally described as structural refurbishment include maintenance jobs, 
such a  painting, gutter cleaning and window  cleaning . 
 
 
 
  
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  5. Planning  and managing projects  
 
5.1 Key planning considerations  
General  
 
The issues in  5.1.1  to 5.1.8  should  be addressed , as appropriate, whe n planning demolition projects. 
Sufficient lead -in time should be allocated  for completion  of these activities.  
 
5.1.1  Effective site knowledge   
An assessment and survey of  the site should  be planned  to identify the following, as far as  
possible:   
a) the extent of decommissioning.   
b) details of the isolation or removal of services and  details of temporary supplies.   
c) knowledge and history of the structure, including form, materi als of construction, structural 
interactions and location.  
 
d) isolation and protection measu res for adjacent  structures.  
e) hazardous materials.  
f) previous uses of  the site.  
5.1.2  Complying with legal requirements  
5.1.2.1   legislation  
Arrangements should be put  in place to ensure compliance with legislation in a number of different related 
fields, including  the following:  
a) waste management regulation, 2006  
b) reuse and  recycling.  
c) control and m inimization of nuisances  to the neighboring site (s)  including  dust, noise, vibration, smoke  
and traffic movement and management.  
 
d) air overpressure.  
e) environmental protection, including prevention of pollution.  
f) occupational safety and health Act, 2007  
g) planning (including listed buildings and party wall constraints ).  
h) building regulations (Demolitions  and construction safety rules)  
i) highways and roads  
j) factories (Building operations and works of engineering construction) rules of 1984  
 
5.1.2.2  permissions, consents and licenses  
 
General  
 
Early consideration should be given  as to whether any permissions , consents or permits/ licenses  are 
required  for the  works and whether any special  measures need to be put  in place, particularly for works  on 
dangerous  struc tures or special sites ( e.g. nuclear sites)  and for works  which could:   DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    7 a)  affect a public or private road or highway, e.g.  works which necessitate:   
i. the partial or total  closure of the road or highway;  
 
ii. the erection of temporary structures (e.g.  scaffolds, fans, screens , hoardings and supports) on or  
over the  road or highway;  
 
iii. the use of  plant or equipment on or  over the  road or highway; and  
 
iv. the storage of site vehicles  on the  road or highway;  
 
b) affect features outside the curtilage of the site ( e.g.  footway lights, vaults and other voids under  a 
highway);  
c) affect access routes , for example , to an adjoining property or utilities.  
d) involve scaffolding  or a crane jib passing over an adjoining  property; or  
e)  involve the  burning of waste in the open on site . 
 
5.1.2.2.1  heritage sites  
The relevant  County Planning  Authority  should be consulted  in good time for advice as to:  
 
a)    whether consent is required for:  
 
i. demolition or partial demolition of a building or other structure that is a designated heritage asset or  
is otherwise considered to have heritage significance meriting consi deration in planning decisions; 
and 
ii. work involving disturbance of the ground ( such as removal of soil, foundations or buried 
services) in  an area  that is considered to be of  archaeological significance;  
 
b) what information will be required  in any application ; and  
c) whether the County Planning Authority  intends to:  
i. place restrictions on the  work, such as  prohibiting alteration or demolition of certain parts of 
the structure, or require the use of  non-contemporary materials or techniques, all of which 
could have cost and time implications; or   
ii. require consultation with specialist bodies, whic h could again have a significant influence on 
project  timing . 
 
Where necessary, c onsents should be applied  for and  obtained before demolition activities 
commence.  The timetable for applications  and consents should also be established  with the  County 
Planning Authority , and taken into  account in th e programme for work  on site . 
 
5.1.3  Programme management  
 
A detailed programme and timetable of events, as appropriate, should be prepared, detailing the 
following.  
a) the scheme, sequence and method of proposed demolition.  
b) the plant required and its usage.  
c) traffic management , the plan for controlling  traffic to, from  and within the site .    
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  d) the management of arisings,  including likely types and amounts, removal and temporary storage 
on site, and  options for reuse , recycling, recovery, disposal, etc. , where  appropriate.  
e) contingency arrangements, e.g.  for partial  collapses or misfires when explosives are used . 
f) the agreed start and completion dates.  
g) any limitations, e.g.  tidal, nightworks, seasonal.  
 
5.1.4  Prote ction of the publ ic 
 
Arrangements for protecting  members of the public should include the following : 
 
a) site security, including the provision of, for example , suitable fencing and/or barriers.  
b) the control of spectators and/or site visitors . 
c) exclusion zones  outside the site boundaries  during critical aspects  of the work, when appropriate.  
d) containment of demolition materials . 
 
5.1.4.1  Precautions to be observed before demolition work  
 
a) Before beginning the actual work of demolition, a careful study shall be made of the structure which is 
to be pulled down and also of all its surroundings. This shall, in particular, include study of the manner 
in which the various parts of the building to be demolished are supported and how far the stage by 
stage demolition will affec t the safety of the adjoining structure. A definite plan of procedure for t he 
demolition work, depending on the manner in which the loads of the various structural parts are 
supported, shall be prepared and approved by the engineer -in-charge and this shall  be followed as 
closely as possible, in actual execution of the demolition work.  
 
b) Before the commencement of each stage of demolition, the foreman shall brief the workmen in detail 
regarding the safety aspects to be kept in view.  
c)  Before any demolition wor k is started, every sidewalk or road adjacent to the work likely to be affected 
shall be closed  and /or be adequately  protected.  
 
d) Children and members of the public shall be kept out of the building and the adjoining yard.  
 
e)  If the structure to be demo lished is more than two storeyed  or 7.5 m high, measured from the sidewalk 
or street which cannot be closed or safely diverted, and the horizontal distance from the inside of the 
sidewalk to the structure is 4.5 m or less, a sub stantial sidewalk shed  shall be constructed over the 
entire length of the sidewalk adjacent to the structure of sufficient width with a view to accommodating 
the pedestrian traffic without causing congestion. The sidewalk shed shall be lighted sufficiently to 
ensure safety at all tim es. 
 
f)  A toe board of at least 1 m high above the roof of the shed shall be provided on the outside edge and 
ends of the sidewalk shed. Such boards may be vertical or inclined outward at not more than 45 
degrees.  
 
g)  Except where the roof of a sidewalk shed solidly abuts the structure, the face of the sidewalk shed 
towards the building shall be completely closed by providing sheathing /planking to prevent falling 
material from penetrating into the shed.  
 
h) The roof of sidewalk sheds shall be capable of sustaining a load of 73 N/mm2. Only in exceptional 
cases, say due to lack of other space, the storing of material on a sidewalk shed may be permitted in 
which case the shed shall be designed for a load of 146 N/mm2. 
 DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    9 i) Roof  of sidewalk shed shall be designed taking into account the impact of the falling debris.  
By frequent removal of loads it shall be ensured that the maximum load, at any time, on the roof of 
work shed is not more than 6000 N/m2. The height of sidewalk shed shall be such as to give a 
minimum clearance of 2.4 m  
 
j)  Sidewalk shed opening for loading purposes, shall be kept closed at all-time except during actual 
loading operations.  
 
k)  The deck flooring of the sidewalk shed shall consist of plank of not less than 2 0 mm in thickness 
closely laid and deck made watertight.  
 
l) All members of the shed shall be adequately braced and connected to resist displacement of members 
or distortion of framework.  
 
m) Where workers’ entrances to the building being demolished are not comp letely protected by sidewalk 
sheds, all such entrances shall be protected by canopies extending from the face of the building to a 
point not less than 2.5 m from it. In such case such overhead protection shall be at least 0.6 m wider 
than the building entr ance or opening and every canopy shall be as strong as the sidewalk shed.  
 
 
It should be ensured that the demolition operations do not, at any stage, endanger the safety of the adjoining 
buildings. Moreover, the nuisance effect of the demolishing work on the use of the adjacent buildings should 
be kept to the minimum.  
 
No structure or part of the structure or any floor or temporary support or scaffold, side wall or any device for 
equipment shall be loaded in excess of the safe carrying capacity, in its the n existing condition.  
 
5.1.5  Environmental manage ment   
The need for the  following should be assessed  during the planning process:  
a) control of noise at the site boundaries ; 
b) control of dust emissions ; 
c) waste management, including  reduction, reuse and recycling;  
d) minimization of materials haulage;  
e) bunding arrangements for storage  and dispensing of fuel oils ; 
f) wheel washing plant and road -cleani ng arrangements, where required;  
g) skip or truck sheeting arrangements;  
h) arrangements for dealing  with hazardous materials, e.g.  flammable materials, gases, haza rdous liquids 
and asbestos;  
i) anticipated values of air overp ressure and ground vibration;  
j) areas of  conserva tion, including flora and fauna;  
k) minimizing landfill;  
l) carbon consumption/agenda.  
 
5.1.5.1  Duties of  contractors  
 
 Contractors  should:  
  
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  a) consider waste minimization and recycling in accordance with the waste management hierarchy during 
the planning stages, and implement systems to prevent downs tream breaches in environmental 
legislation, such as  the duty of care, and illegal deposit of waste.   
b) give priority  to minimization before construction, for example , through designs, layout and other 
decisions, with preference given to on -site reuse and recycling, followed by off -site reuse and 
recycling, r ecovery and disposal.  
 
c) identify the amount of space available on site for processing  materials , e.g.  where on -site processing 
is impractical, it might be more  productive to send the waste to a materials recycling facility ( MRF, also 
known  as a “transfer s tation”).  
 
d) obtain advice during planning from relevant  enforcement A uthorities as to what will be allowed  for the  
burning of materials, both by open fire or  incineration, as these activities are subject  to local and  
national restrictions  
 
5.1.6  Occupational safety of the workforce   
General  
 
Measures for the  following should be put  in place:  
 
a) obtaining details of personnel access and  working platforms, including the procedure for their  
maintenance and subsequent removal as the structure is reduced.  
 
b) establishing appropriate working  spaces and exclusion zones.  
c) protecting the workforce, including reference to any permit  to work procedures.  
 
d) providing effective communications, including warning signs and  signals.  
 
5.1.6.1  Specific safety p recautions  
a) On every demolition job, safety signs shall be conspicuously posted all around the structure. All doors 
and openings giving access to the structure shall be kept barricaded or manned except during the 
actual passage of workmen or equipment. However, provision shall be made for at least two 
independent exits for  
b) Escape of workmen during any emergency.  
 
c) during nights, red lights shall be placed on or about al l the barricades.  
 
d) Where in any work of demolition it is imperative, because of danger existing, to ensure that no 
unauthorized person shall enter the site of demolition outside working hours; a security guard should be 
employed. In addition to securing the site he shall also be responsible for maintaining all notices, lights 
and barricades . 
 
e) All the necessary safety appliances  shall be issued to the workers and their use explained. It shall be 
ensured that the workers are using all the necessary  safety appliances  while at work.  
 
f) The removal of a member may weaken the side wall of an adjoining structure and to prevent possible 
damage, these walls shall be supported until such time as permanent protection is provided. In case 
any danger is anticipated to th e adjoining structure, the same shall be vacated to avoid any danger to 
human life.  
 
g) The power on all electrical service lines shall be shut off and all such lines cut or disconnected  DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    11 at or outside the property line, before the demolition w ork is started. Prior to disconnecting  of such lines, 
the necessary approval shall be obtained from the electrical authorities concerned. The only exception 
will be any power lines required for demolition work itself.  
 
h) All gas, water steam and other service lines shall be  shut off and capped or otherwise controlled at or 
outside the building line, before demolition work is started.  
 
i) All the mains and meters of the building shall be removed or protected from damage.  
 
j) If a structure to be demolished has been partially wrecke d by fire, explosion or other catastrophe, the 
walls and damaged roofs shall be shored or braced suitably.  
 
k) Walkways and passageways shall be provided for the use of the workmen who shall be instructed to 
use them and all such walkways and passageways shal l be kept adequately lighted, free from debris 
and other materials.  
 
l) All nails in any kind of lumber shall be withdrawn, hammered or bent over as soon as such lumber is 
removed, from the structure being demolished, and placed in piles for future cleaning or burning . 
 
5.1.7  Occupational health of the workforce   
Processes for the  following should be put  in place in accordance  with the relevant legislations:  
 
a) Hazard recognition, risk assessments and control measures for:  
 
i. substances potentially hazardous to health, e.g.  from heavy metals or other toxic substances , 
including when working with materials which can be reused  or recycled; and  
 
ii. exposures to harmful substances such as  asbestos and radioactivity.  
 
b) assessments and control measures for noise  and dust on sites . 
c) identification of deleterious atmospheres, such as  oxygen deficiency in confined spaces.  
 
d) hazard recognition and risk assessments for the  need for, and  the provision of, appropriate  personal 
protective equipment (PPE).  
 
e) appropriate welfare arrangements, including for when  the work involves exposure to contaminated 
materials or dirty work . 
 
f) health monitoring of all staff.  
 
5.1.8  Predicted weather  conditions  
 
Arrangements should be made  where appropriate for liaison  with, for example , the Meteorological 
Department  to obtain forecasts of sudden and severe weather changes, such as  strong winds, lightning, 
snow and heavy rain, and  indications of how these can affect  the planned works and programme . 
 
5.2 Planning and managing for site work  
5.2.1  recommended s ystems of work  
a) demolition works should be planned  in such a  way that  it is undertaken using systems of work that 
take into consideration safety, health, the environment  and efficiency.   
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved   
b) before demolition work is started, glazed sash, glazed doors and windows, etc., shall be removed.  All 
fragile and loose fixtures shall be removed. The lath and all loose plaster shall be stripped off throughout 
the entire building. This is advantageous because it reduces glass brea kage and also eliminates a large 
amount of dust producing material before more substantial parts of the buildings are removed.  
 
c) all well openings which extend down to floor level shall be barricaded to a height of not less than one 
metre above the floor level. This provision shall not apply to the ground level floor.  
 
d) all those involved from concept through tender to contract execution should ensure effective 
planning and communication, and the provision of sufficient time to allow the execution of a 
successful and efficient project.   
e) the timescales required for the  acquisition of any licenses  or permits should be allowed for in  the 
programming of works.   
f) after the contract has been  awarded, and before work commences, the contractor should determine 
the proposed safe sequence  of operations on the  basis of  an assessment  of the comparative risks, 
related specifically  to the site and conditions. This sequence should be used  to assess an d expand 
the construction phase plan (CPP) for the  tender and proposed programme of works. The expanded 
plan for the  tender should form the basis of  the CCP (demolition plan) for the  demolition.  
 
g) the methods of work should allow for demolition  activities and site clearance  as stipulated by the 
contract, taking account of any constraints  imposed by the client.  Adequate time should be allowed  for 
setting  up the  site prior  to work commencing and for executing  the works.  
 
h) the demolition work shall be pr oceeded  within such a way that  it causes the least damage and nuisance 
to the adjoining building and the members of the public, and  also satisfies  all safety requirements to 
avoid any accidents.  All existing fixtures required during demolition operations shall be  well protected 
with substantial covering to the entire satisfaction of the rules and regulations of the undertakings or they 
shall be temporarily relocated.  
i)  all floor openings and shafts not used for material chutes shall be floored over and be enclosed with 
guard rails and toe boards.  
 
5.2.2  Risk management  
General   
 
Tenderers/contractors should look for the  hazards in the project, including how and where the work could be 
done  and the equipment and materials used.  
 
When planning methods and sequences of work, a suitable and sufficient risk assessment should be carried  
out and recorded. This should include selecting methods, materials and equipment to remove or minimize 
risk from work.  
 
5.2.2.1  Risk assessment  
 
The following principles of risk assessment should be followed  when determinin g methods and sequences of 
work:  
 
a) identify the hazards as sociated with the proposed work;  
 
b) consider who might be harmed  and how, including workers, site visitors , members of the public and 
anyone affected by the work;  DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    13  
c) evaluate the risks and identify the precautions required by, for example , comparison with good practice 
and categorization of risk level ( likelihood and severity);  
 
d) record the findings and implement the control measures for the residual risks;  
 
e) review the  risk assessment and update if necessary.  
 
The risk assessment should take into account any constraints  that the client has identified, but the 
contractor should be given  the freedom to determine the proposed methods of demol ition.   
The risk assessment should identify the risks associated with the work and enable the contractor to select 
appropriate demolition solutions that remove or reduce the risks before the work commences.   
The contractor should then select the most suita ble methods of demolition which include measures to 
properly control any remaining  risks.  
 
5.2.2.2  Risk control  
 
The steps required for effective  risk control are simple . First, a determination should be made  as to 
whether the hazard can be eliminated  altogether. If not, consideration should be given  to the control 
measures required to reduce harm, e.g.  equipment, systems of work and sequencing. If the risk is 
unacceptable, alternative control measures should be applied  till the risk is acceptably low . 
 
The following principles should be applied  to the control of risk:  
 
a) if possible, avoid the risk completely by using safer alternative methods or materials.  
 
b) address risks at source, rather than using superficial control measures that result in a high or  
unnecessary residual risk remaining in place.  
 
c) wherever possible, adapt the work to the individual, particularly in the choice of work equipment and 
methods of work, as this makes  the work less monotonous, improves concentration and reduces the 
temptation  to improvise equipment and methods.  
 
d) take advantage  of technological progress, which often offers opportunities for safer  and more efficient 
working methods.  
 
e) incorporate the protective and preventive measures into a coherent plan to reduce progressively 
those risks which cannot altogether be avoided , taking into account working conditions, organizational 
factors, the working environment and social factors . 
 
5.3 Competencies and training  
5.3.1   Competencies  
 
All demolition and structural alteration activities should be carefully  planned and carried out by competent 
practitioners and organizations. People making appointments should take reasonable steps to ensure that 
those appointed are competent for what  they are expected  to do.  Likewise, those  accepting such 
appointments should only do so  if they are competent  to undertake the particular activity. Clients and  
procurers of demolition works have a key role and  should ensure that all contractors, designers and other  
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  team members that they propose to appoint have either the competence to carry out  the work themselves 
or have engaged the services of  an individual  or organization with these competencies.  
 
5.3.2  Training  
 
Management should ensure that the necessary levels  of competence exist and  are developed  by 
appropriate training as required. This should include industry -recognized training schemes intended to 
ensure that managers, supervisors and operatives in the demolition industry are competent  at the level 
of exper ience that they claim and  that they have received suitable training in, for example, health and 
safety and waste management.  
 
5.4 Personal protective  equipment (PPE) on site  
 
The method of work chosen should ensure that the exposure to risk is minimized to such an extent  that 
PPE is required to provide protection only against those risks that cannot be avoided  by any other  
planned approach to the work.  The following shall therefore be observed:  
 
a) as a result of the known risks to health and safety that are pr esent  during demolition work, all 
personnel should be required  to wear, in addition to safety helmets, sui table basic protective  
equipment  such as  footwear, gloves and high -visibility clothing as appropriate. Additional PPE, e.g.  
eye protection , fall arrest systems (including full body harnesses), hearing protection, respiratory 
protection equipment (RPE) and ori -nasal masks, should  be issued  only when  alternative methods of 
work which do not  require additional protective equipment have been ass essed and found to be 
unsuitable  when hot cutting).   
b) appropriate training should be provided  in the use of  PPE, when needed.   
c) such equipment should be suitably  maintained and stored to ensure continued levels of  required 
performance.   
Examples of hazards w hich should be catered  for through  the provision of planned control measures 
include the following.   
i. chemicals which have been stored or used.   
ii. arisings from  lead paint, asbestos, dust, fumes or substances  
 
d) contractors should establish emergency procedures to be followed  in the event of premature collapse, 
fire or  explosion. Suitable and sufficient emergency procedures should be prepared  in an emergency  
plan for identified  scenarios, in association, as appropr iate, with the emergency services, public  and 
private bodies such as  local authorities , transport operators, housing managers, waterways operators, 
and health, safety and environment regulators. The emergency plan should set out  appropriate actions 
(including limits of  actions) and identify with whom the responsibilities are placed . The emergency plan 
should be incorporated  into the demolition plan.  
 
e) all persons on site should  be instructed  in the emergency procedures. All those who could come on to  
site should  also be made  aware of the procedures. A means of contacting the emergency services 
should  always be available  while work is in progress, even on small jobs . 
 
f) the arrangements should be tested  by carrying out exercises at su itable intervals to familiarize site 
personnel  with the procedures, to test their effectiveness and, where necessary, to ensure effective 
liaison with the emergency services and  others as appropriate.  
 DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    15 g) where there is a risk of fire, suitable  fire precautio ns should be put  in place including  adequate escape 
routes, as appropriate, identification and illumination of those routes, exits that  are readily  usable, means 
of raising the alarm, and firefighting  equipment and emergency plans.  
 
5.5 Permit to work procedures  
5.5.1  Permit to work  
An employer  shall issue a permit to work to any employee, likely to be exposed to hazardous work 
processes o r hazardous working environment  in order to secure the safety and health of the employee.  
Such work and work  environment that may require permit to work include:  
 
a)    work on or  near live electrical plant;  
 
b)    entry to or work in  confined spaces;  
 
c)    moving machinery that requires isolation before approach; or  
d)    hot work.  
 
The permit to work procedure should be used : 
 
i. to ensure that personnel working in the restricted area are aware  of the hazards involved, and the 
identity, nature an d extent of the work to be done and precautions to be taken.  
 
ii. to ensure that a formal check is undertaken to confirm elements of a safe system of work are in  
place before people are allowed  to enter or work in the restricted area;   
iii. where there is a need to exclude or coordinate other people or their activities which could affect 
work or condition s in the restricted area; and   
iv. if the work requires the authorization of more than one person, or there is a time limit on entry . 
 
The aim of  a permit to work procedure should be to  provide a managed, safe, restricted working area. The 
permit to work procedure, including the issue of  a permit, should be regarded  as an integrated  part of a “safe 
system of work”, but does not by itself make  the job safe .  The permit to work procedure s hould support that 
safe system  and provide a record of activities, authorizations and timings for the  protection of those 
undertaking the activities, and sometimes others.  
There should be sufficient  procedural control of temporary works, including the appointment of a temporary 
works coordinator with responsibility for ensuring  that structural stability is maintained throughout temporary 
structural states during operations. An assessment should be ma de as to whether a permit  to work system is 
appropriate.  
 
5.5.2  Emergency arrangements  
 
Emergency arrangements should be put  in place before entering a confined space. The  following  
should be provided , as appropriate:  
 
a) rescue and  resuscitation equipment.   
b) measures for raising  the alarm and rescue.  
c) measures for safeguarding  the rescuers.  
d) fire safety measures.   
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  e) control of plant.  
f) first aid.   
g) public emergency  services.  
h) effective communications.  
 
5.5.3  Welfare and  first aid  
 
5.5.3.1  Welfare provision  
 
Welfare facilities should be provided  and maintained at readily accessible places for the  duration of the 
works. These facilities  should be suitable  and sufficient and include toilet and w ashing facilities , portable 
drinking water and showers, if required by the nature of the work for health  reasons.   
Accommodation should be provided  in the immediate vicinity, or  should be conveniently accessible for the  
place of work and for shelter , drying wet clothing and storing clothing not worn during working hours  
 
5.5.3.2  First aid  
 
Those undertaking  demolition activities should ensure that adequate first aid  provision is made 
available. Those on site should  be informed  of the first aid  provisions that have been made for them .The 
level of  first aid to  be provided  should be determined  initially by risk assessments carried ou t prior to the 
work commencing.  
 
6. Removal of materials  
General  
There shall be an approved  waste disposal contract  in place in order to effectively dispose of the    
demolished materials as appropriate . An approved site by the regulatory A uthority should be used for the  
disposal . Once the demolished materials have been ascertained to be hazardous -free by the relevant 
Authority, d isposal can be through sale, recycling, reuse o r reclamation of disused sites. The need  for 
temporary , auxiliary and permanent items  should be assessed , taking account of the need to manage the 
waste streams from the site . The following  methods may  be used:  
 
a) through chutes  
i. Wooden or metal chutes may be provided for removal of materials. The chutes shall preferably be 
provided at the centre of the building for efficient disposal of debris.  Chutes, if provided at an angle 
of more than 45” from the horizontal, shall be entirely enclosed on all the four sides, except for 
opening at  or about the floor level for receiving the materials.  
 
ii. Opening for the chutes  shall not exceed 1.20 m in height measured along the wall of the chute and 
in all storeys below the top floor such opening shall be kept closed when not in use.  To prevent the 
descending material attaining a dangerous speed, chute shall not extend in an unbroken line for 
more than two storeys. A gate or stop shall be provided with suitable means for closing at the bottom 
of each chute to stop the flow of materials.  
 
iii. Chutes at an angle of less than 45” to the horizontal may be left open on the upper side provided  
that at the point where such a chute discharges into a chute steeper than 45” to the horizontal, the 
top of the steeper chute shall be boarded over to p reven t the escape of materials.  
 DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    17 iv. Any opening into which workmen dump debris at the top of chute shall be guarded by a substantial 
guard rail extending at least one metre above the level of the floor or other surface on which men 
stand to dump the materials into  the chute.  
 
v. A toe board or bumper, not less than 50 mm thick and 150 mm high shall be provided at each chute 
opening, if the material is dumped from the wheel barrows. Any space between the chute and the 
edge of the opening in the floor through which it p asses shall be solidly planked over.  
 
b) through holes in the floor  
i. Debris may also be dropped through holes in the floor without the use of chutes. In such a case the 
total area of the hole cut in any intermediate floor, one which lies between floor that is being 
demolished and the storage floor shall not exceed 25 percent of such floor area. It shall be ensured 
that the storage floor is of adequate strength to withstand the impact of the falling material.  
 
ii. Openings in all the floors below the floor from whic h materials are being removed, shall be protected 
by standard railings and toe boards or preferably planked over if the holes are not being used for 
dumping materials.  
 
iii. All intermediate floor openings for passage of materials shall be completely enclosed w ith barricades 
or guard rails not less than one-metre -high and at a distance of not less than one metre from the 
edge of general opening. No barricades or guard rails shall be removed until the storey immediately 
above has been demolished down to the floor  line and all debris cleared from the floor.  
 
iv. When the cutting of a hole in an intermediate floor between the storage floor and the floor which is 
being demolished makes the intermediate floor or any portion of it unsafe, then such intermediate 
floor shall  be properly shored. It shall also be ensured that the supporting walls are not kept without 
adequate lateral restraints.  
 
6.1 Removal of debris  
a) As demolition work proceeds, the released serviceable materials of different types shall be separated 
from the unservic eable lot at suitable time intervals an d properly stocked to prevent obstruction  where 
demolition work is being done.  
 
b) The unserviceable materials  obtained during demolition shall be collected in well -formed heaps at 
properly selected places, keepi ng in view safe conditions for workmen in the area. The height of each 
unserviceable  materials  heap shall be limited to ensure its not toppling over or otherwise endangering 
the safety of workmen or passersby.  
 
c) These materials shall be removed from the demolition site to a location as required by the relevant 
Authority. Depending on the space available at the demolition site, this operation of conveying  them  to 
its final disposal site  may have to be carried out a number of times durin g the demolition work. In any 
case, the  demolition work shall not be considered as completed and the area declared fit for further 
occupation till all the unserviceable materials  have  been carried to its final disposal site  and the 
demolition area tidied u p. 
 
d) Materials which are likely to cause dust nuisance or undue environmental pollution in any other way, 
shall be removed from the site at the earliest and till then , they shall be suitably covered. Such materials 
shall be covered during transportation also.  
  
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  e) Unauthorized use of the debris (or the unserviceable materials)  in any work shall not be permitted. The 
released  materials class ified as ‘serviceable’ shall be  inspected by a competent person before being  
used.  
 
6.1.1  Airborne dust control  
The following mitigation measures should be used to control dust emission during demolition work:  
a) provide sufficient misting water sprays  to reduce airborne dust;  
b) keep stockpiles for the shortest time possible;  
c) avoid dust -generatin g work on high wind days.  
 
7. Stairs, passageways and ladders  
a) Stairs and stair railings, passageways and  ladders shall be left in place as long as possible.  
b) For the use of l adders, provisions laid down in  ISO 14122 shall be followed.  
c) All stairs, passageways and ladders to be used by workmen during the process of demolition shall be 
maintained in a safe condition.  
d) Ladders or their side rail extend not less than 1. 0 m above the floor or platform to which  such ladder 
gives access.  
e) All ladders shall be secured against, slipping out at the bottom and against movement in any direction 
at the top.  
 
8. Demolition of walls  
a) While walls or sections of masonry are being demolished, it shall be ensured that they are not al lowed 
to fall as single mass upon the floors of the building that are being demolished so as to exceed the safe 
carrying capacity of the floors. Overloading of floors shall be prevented by removing the accumulating 
debris through chutes or by other means i mmediately. The floor shall be inspected by the engineer -in-
charge before undertaking demolition work and if the same is found to be incapable to carry the load of 
the debris, necessary additional precautions shall be taken so as to prevent any possible unexpected 
collapse of the floor.  
 
b) walls shall be removed part by part. Stages shall be provided for the men to work on, if the walls are 
very thin and dangerous to work by standing over them.  
 
c) no section of wall whose height is more than 15 times of thickness, shall be permitted to stand without 
lateral bracing unless such wall is in good condition and was originally designed to stand without such 
lateral bracing or support.  
 
d) structural or load supporting members on any floor shall not be cut or remov ed until all the storeys 
above that floor have been demolished and removed.  
 
e) before demolishing any interior or exterior wall within 3 m of the opening in the floor immediately below, 
such opening shall be substantially planked over, unless access is denie d to workmen to that portion of 
the area of the floor immediately below the opening, in the floor of the storey being demolished, where 
any debris pieces passing through this opening may fall.  
 
f) in framed structures, the steel frame may be left in place during demolition of masonry work. Where this 
is done, all steel beams, girders, etc., shall be cleared of all loose  materials as the demolition of 
masonry work  progress downward provided it is stil l strong enough to stand as an independent 
structure.  
 DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    19 g) walkways shall be provided to enable workmen to reach or leave their work on any scaffold or wall. 
Such walkways shall be not less than 3 planks , nor less than 0. 8 m in width. At the com pletion of each  
day’s work, all walls shall be lef t stable to avoid any danger of getting overturned.  
 
h) foundation  walls which serve as retaining walls to suppor t earth or adjoining structure, shall not be 
demolished until such an adjoining structure has  been underpinned or braced and the e arth removed by 
sheet piling or sheathing.  
 
9. Demolition of floor s 
a) In cutting holes in a floor which spans in one direction, a slit of width not exceeding 300 mm shall be cut 
at the first stage for the entire length o f the slab along which it spans. The opening shall thereafter be 
increased to the desired width by suitable instalments.  
 
b) Planks of sufficient strength not less than 50 mm thick and 250 mm wide shall be provide d at spacing 
not greater than 0. 4 mm for the w orkmen to work. The length of planks shall not be less than 2 mm. 
These planks shall be so placed as to give workmen firm support to guard against any unexpected floor 
collapse . 
 
c) Stringers of ample strength shall be installed to sup port the planks where ne cessary and the ends of 
such stringer shall be supported by floor beams, girders and n ot by floor slab alone.  
 
d) When floor s are being removed, no workmen shall be allowed to work in the area, directly un derneath 
and such area shall be barricaded to prevent access to it.  
 
e) The demol ition of floor shall be started only after the floor i n question and the surrounding floor ar ea for 
a distance of 6. 0 m have been entirely cle ared of persons, and the debris and othe r unnecessary 
material removed.  
 
f) Planks used  for temporary protection shall be sound and a t least 50 mm thick. They shall be laid close 
together with the ends having at least 100  mm bearing over solid support to prevent ti pping under load. 
If corrugated GI Sheets are  used for temporary protection, it sha ll be se cured to the solid support with 
suitable framework.  
 
10. Demolition of steel structures  
 
a) When a derrick is used, care shall be taken to see that the floor on which it is supported is amply strong 
for the loading so imposed. If necessary,  heavy planking shall be used to distribute the load to floor 
beam and girders.  
 
b) Overloading of equipment shall not be allowed.  
 
c) Tag lines shall be used on all materials being lowered or hoisted up and a standard  signal system shall 
be used and the workmen  instructed on the signals.  
 
d) No person shall be permitted to ride the load line.  
 
e) No beams shall be cut until precautions have been taken to prevent it from swinging freely and possibly 
striking any worker or equipment to any part of the structure being de molished.  
  
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  f) All st ructural steel members shall be lowered fro m the building and shall not be allowed to drop.  
 
11. Demolition of exterior walls of multistoreyed structures  
 
a) In demolition of exterior wall s of multistoreyed structure, it is advisable to provide catch platform of 
heavy planking to prevent injuries to the worker working below and to the public, when the external 
walls are more than 20 m in height.  
 
b) Such catch platform shall be constructed and maintained not more than 3 storeys below the storey from 
which exterior wall is being demolished. When demolition has progressed to within 3 storeys of ground 
level, catch platform will not be considered necessary.  
 
c) Catch platforms shall not be less than 1.5 m in width, measured in a horizontal direction from the face of 
the structure and shall consist of outriggers and planks. Planks shall be laid tight together, without 
openings between them and the walls. Catch platform shall be provided with a continuou s solid parapet 
along its outer edge of at least 1 m height. The parapet shall be constructed of the same specification 
as the platform.  
 
d) Catch platform can be constructed of material other than wood also, provided such material is of equal 
strength.  
 
e) Catch platform shall be capable of sustaining a live load of not less than 6 100 N/m2. 
 
f) The outriggers shall be of ample strength and shall not be spaced more than 3 m apart.  
 
g) Materials shall not be dumped on catch platform nor such catch platform shall be use d for the storage 
of materials.  
 
12. Mechanical demolition  
When demolition is to be performed by mechanical devices, such as high reach arm, weight ball and power 
shovels, the following additional precautions may be observed:  
a) The area shall be barricaded for a  minimum distance of 1 ½ times  the height of the wall;  
b) While the mechanical device is in operation, no workmen shall be allowed to enter the building being 
demolished;  
c) The device shall be so located  to avoid, or be guarded  against  falling debris; and  
d) The mechanical device when being used  shall not cause any damage to adjacent  structure, power line, 
etc. 
 
13. Recommendations for demolition of certain special types and elements of  
structures  
13.1 roof trusses  
a) If a building has a pitched roof, the roof structure should be removed to wall plate level by hand 
methods. Sufficient purlins and bracing should be retained to ensure stability of the remaining roof 
trusses while each individual truss is removed progressively  
 
b) Temporary bracing should be added, where necessary, to maintain stability. The end frame opposite to 
the end where dismantling is commenced, or a convenie nt intermediate frame should be 
independently and securely guyed in both directions before work starts.  
 DKS 2867 : 2018  
 
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved    21 c) On no account should the bottom tie of  roof trusses be cut until the principal rafters are prevented from 
making outward movement.  
 
13.2 heavy floor beams  
Heavy baulks of timber and steel beams should  be supported before cutting at the extremities and  should 
then be lowered to a safe working place.  
 
13.3 jack arches  
Where tie rods are present between main supporting  beams, these should not be cut until  after the arch or 
series of arches in  the floor  have  been removed. Particular care sh ould be  exercised and full examination of 
this type of  structure undertaken before demolition  is commenced . The floor should be  demolished in strips 
parallel to the span of the  arch rings ( at right angles to the main floor  beams)  
 
13.4 brick arches  
a) Expert advice should be obtained and, at all stages of the demolition, the closest supervision should be 
given by persons ful ly experienced and conversant with  the type of work to ensure that the structure is 
stable at all times.  
 
b) As much dead load as possible may be removed provided it does not interfere with the  stability of the  
main arch rings but it should be noted that the load -carrying capacity  of many old arches relies on the 
filing between the spandrels. On no account should the restraining influence of the abutments be 
removed before the dead load of the s pandrel fill and the arch rings are removed.  
 
c) Special temporary support shall be provided in the case of skew bridges.  
 
d) A single span arch can be demolished by hand by cutting narrow segments progressively  from each 
springing parallel to the span of the arch, until the width of the arch has been reduced to a minimum 
which can then be collapsed.  
 
e) Where it is impossible to allow debris to fall to the ground below, centering designed to carry the load 
should be  erected and the arch demolished progressively. The design of the centering sh ould make 
appropriate allowance for impact.  
 
f) Where deliberate collapse is feasible the crown may be broken by the demolition ball while  working 
progressively from edges to the ce ntre. 
 
g) Where feasible and appropriate, c ollapse  of the structure can be effected in one action by the use of 
explosives. Charges should be inserted into boreholes drilled in both arch and abutments. This method 
is the most effective for demolition of tall viaducts.  
 
h) In multi -span arches before individu al spans are removed, lateral restraint should be provided at the 
springing level. Demolition may then proceed as for a single span;  care being taken to demolish the 
spandrels down to the sprin ging line as the work proceeds.  Where explosives are used it is  preferable 
to ensure the collapse of the whole structure in one operation to obviate the chance of leaving unstable 
portions standing.  
 
13.5 cantilevers ( not part of a f ramed  structure)  
A cantilever type of construction depends for its stability on the superimposed structure. Canopies, cornices, 
staircases and balconies  should be demolished or supported before the tailing down load is removed.  
  
 
 
 
 
 
 
 
 
© KEBS 2018 — All rights reserved  13.6 in-situ reinforced c oncrete  
a) Before commencing demolition, the nature and condition of the concrete, the condition and position of 
reinforcement, and the possibility of lack of continuity of reinforcement should be ascertained.  
 
b) Attention should be paid to the principles of the  structural design to determine which parts of the 
structure depend on each other t o maintain overall stability.  
 
c) Demolition should be commenced by removing partition s and external non -load bearing cladding. It 
should be noted that in some buildings the frame may rely on the panel w alls for stability.  
 
d) Where hand demolition methods are t o be used, the  following procedures should be used:  
i. Reinforced concrete beams  
For bea ms, a supporting rope should be attached  to the beam. Then the concrete should be removed 
from both end s by pneuma tic drill and the reinforcement exposed . The reinforcement should then be cut 
in such a way as to allow the beam to be low ered under control to the floor.  
 
ii. Reinforced concrete columns  
For co lumns, the reinforcement should be expose d at the base after restraining wire g uy ropes have been 
placed round the membe r at the top. The reinforcement should then be cut in such a way as to all ow the 
column to be pulled down to the f loor under control.  
 
iii. Reinforced concrete walls  
Reinforc ed concrete walls should be cut into strip s and demolished as for columns.  
 
iv. Suspended floors and roofs  
Before demolishing suspended floors and roofs, the type of construction should be ascertained. In solid 
slabs, the direction of the main reinforcement should be determined; the slab should then be cut into strips 
parallel to the main reinforcement and demo lished strip by strip.  
Where ribbed construction has been used, the principle of design and method of construction should be 
determined  before demolition is commenced,  care should be taken not to cut the ribs inadvertently.  
 
13.7 Precast reinforced c oncrete  
Precast re inforced concrete units used in a structure are n ormally held in position by the strength of the joints 
made in-situ or on supporting walls, e tc. As such, before starting on demolition, the joint structures and/or 
the supporting mechanisms shall be studied and understood.  
 
In devisin g and following the demolition sequences d ue precaution shall be taken to avoid toppling  over of 
prefabricated units or any other par t of the structure and wherever necessary temporary supports shall be 
provided.  
13.8 Pre-stressed reinforced c oncrete  
Before co mmencing of the demolition work involving such s tructures advice of an engineer expert in such 
demolition shall be obtained and followed.  
13.9 Chimney and s pires  
Before com mencing of the demolition work, involving such st ructures, advice of an engineer expert in such 
demolition shall be obtained and followed.