Advising Employers on Construction Schedules & Programmes
One of the most important factors for the Employer when considering the feasibility of a project and the design is the period required to construct the project and the effects this will have on both utilising the building and financing of the project. Where Employers are not experienced in the construction process and do not have any in-house expertise they will normally rely upon their consultants to advise them on the construction periods for their intended project. Where a project is straightforward and familiar to the consultant this should not present a problem however when a project is complex and large involving specialist equipment and unique design elements then the task of forecasting the time required for the project to be design and constructed is more of a challenge to the Consultant charged with giving the Employer an outline programme for the Works.
Many factors need to be considered when estimating and setting a time required for the execution of a construction project and it is unwise for consultants to merely estimate and set construction periods without taking into account not only the wishes of the Employer but also the effects of the following:
A) The skills and competence of the Employers design team and their experience in the design and management of the particular type of project being undertaken. Although this is a rather delicate subject which may highlight the weakness of the Employers design team, it is important to consider this when estimating the construction period. Invariably weaknesses will come to light with inadequate design later which could involve the Employer in even greater expense as it could to the design team.
B) The availability of a Contractor and or Contractors who are experience and possess the required resources to execute the project, including the construction techniques that are available to these Contractors in relation to where the project is being executed. A Contractor who poses the relevant expertise in a certain type of construction can be the difference between a project’s success and failure. Similarly it is important to identify specialist manufacturers and suppliers which are to be engaged at an early stage and allow for long procurement periods for important elements of a project.
C) Establishment Times required, including preparing management plans and asset management information. Some Employers as a result of their corporate structure or the business they operate in require much greater and detailed quality, risk management and HSE programmes in the execution of not only construction projects but also in all their business activities. Where their partners and suppliers are operating to this standard there may be no effect on the programme, but if these additional requirements are placed on the design team and contractors who generally don’t operate to the same level, then adopting these programmes can incur additional time.
D) The Weather Conditions in the vicinity of the works for the anticipated Construction Period. Regardless of the Contract conditions in respect of extension of time, the fact remains that the programme of the works needs to make allowance for weather conditions particularly the wet seasons.
E) The condition of the Site will affect the time needed for preparatory site works to be completed before construction of the building or other structures can start. Some factors that may increase the construction period would be.
- Extensive Site Profiling – This may involve clearing of existing vegetation and extensive cut or fill operations to establish the required building platform profiles.
- Close Proximity to Adjacent Buildings – Where the site is adjacent other structures or building this may involve the Contractor it undertaking additional temporary support or protection works to both the buildings and their foundations or basements. It may also involve the contractor in obtaining additional approvals and extensive monitoring programmes. In addition the close proximity of building can lead to restrictions on working hours, methods of construction such as vibration and noise restrictions.
- Requirement for Pile Foundations – In Malaysia it is commonplace if not almost universal that any major structure will be supported by piled foundations as a result of the geological conditions that prevail in all but the mountainous areas of the country.
- Rock Excavation – Obviously the drilling and blasting of rock which is encountered on the site will involve the Contractor in considerable extra works and will also limit other works during this period.
- Demolition work prior to construction – In the event that the site has exiting structures which require removal then time will have to be allocated for these operations and the necessary disposal of debris from the site. This may involve not only the above ground elements but also the services and foundations of this structures which as highlighted above will often include piled foundations in Malaysia. Additional problems can be incurred where asbestos is present which can involve the Contractor in time-consuming removal and disposal together with implementing a programme which complies with the health and safety protocol in respect of handling such materials.
- High Water Table – Ground water can present major challenges where the proposed structure involves deep excavations such as basements. It goes beyond the obvious need to keep the excavations free from water and involves the stabilisation of surrounding water table to prevent shrink and heave and the possibility of instability of surrounding buildings. In addition the Contractor may need to consider the environmental issues of disposal of water which is de-watered during construction activities.
- Development approval conditions such as restrictions on work hours, noise and delivery times for material – These types of restrictions normally apply in areas of importance and areas which are subject to a high density of development. In addition consideration needs to be taken of environmental impact assessment reports and subsequent conditions by the Government agencies which will sometimes impose additional restrictions in respect of working methods and protection works.
- Difficult Access to the Site – Site Access difficulties can be as a result of the location or it may be as a result of other factors such as poor infrastructure, transportation hubs such as ports or the lack of transportation due to the isolated location. An example would be large dam or similar civil engineering undertaking which by their nature tend to be away from urban areas often located in difficult to access locations without utilities or transportation infrastructure.
- Relocation or deviation of services – The site may require the relocation of buried or overhead services and any programme should include for the execution of these works together with obtaining the necessary approvals and monitoring by the utility owners and necessary authorities.
- Archaeological, Heritage or Hazardous Materials Survey Requirements – Obviously where a site is known to be of importance it would be best to locate an alternative site for a major development. But in cases where there are no alternative such as refurbishment or similar projects account needs to be taken of the likely impact these will have on the construction schedule.
F) Site Access can entail more than a poor access road to the site. When considering site access in regard to the programme it is important that factors such as transport infrastructure, ports, airports, services, communications and restricted access are also taken into account.
G) Industrial Issues such as labour availability and restrictions can have a major effect on the construction schedule. Government policies in respect of foreign workers and their engagement are subject to constant review as to will be the government policy of countries from which the workers may originate. In addition labour laws may restrict activities and again regard to these laws need to be allowed for in the estimation of a construction schedule.
H) The Complexity of the Project and its design. Projects that are unique, such as the refurbishment of historical, religious or culturally significant buildings, will on the whole require special construction techniques, more highly skilled and specialist resources providing greater attention to detail. This will generally require more time and needs to be allowed for any projected construction schedule for the project. Industrial shed type buildings, and other simple purpose-designed buildings may be substantially fabricated off-site in quality controlled production plants, allowing for the parallel construction of on-site work which should allow for significant time savings to any construction schedule. High-rise or multi-story buildings will on the whole take longer to construct than low-rise structures of a similar floor area due to the difficulties in vertical construction challenges with access material transportation difficulties. Civil construction work is more likely to be affected by weather conditions than building work. Once a building is roofed, it can provide for work to continue during adverse weather conditions.
I) The Geographical Location of the Site. Construction projects can be susceptible to delays and varying construction period as a result of their locations. Projects in urban areas will generally have access to a greater volume and diversity of resources, so there will be less lead time and less lost time in bringing those resources onto the site. It may therefore be easier to maintain or accelerate progress. Projects in the Central Business District will generally have slightly longer construction times because of access difficulties, together with restrictions on working practices and hours. Projects in remote areas will be affected by difficulties in obtaining suitable resources in the form of labour, equipment and materials.
J) The state of the general economy and Construction Market can affect the availability of labour equipment and materials. In a buoyant market all resources become scarcer which not only affects price but inevitably will affect the availability of resources available for the project. It is possible to source alternatives in many instances but where specialist equipment whether it be a gas turbine of bank of high-speed lifts it is sometimes impossible to avoid long lead-in times. Recently just before the 2008 financial crisis the whole industry felt this with the huge construction programmes being carried out in the Middle East and China which effected availability of new plant, raw materials and even skilled labour not only in Malaysia but globally.
K) The likelihood of the Employer requiring to issue variations which can be judged by past performance, completeness of design and the specific project characteristics which in some instances can naturally lead to the need for variations. Where the project is likely to incur large numbers of variations account should be made of this in the construction programme for the Works.
As a matter of good practice consultants charged with developing and advising on the estimated construction period necessary to complete a project they should take account of the above factors and where they deem it necessary conduct a risk analysis using either their experience of similar works or that of others as a basis and developing this by adjusting it to take account of the factors discussed in this article.
There exist various tables and graphs which are published by various organisations and bodies which attempt to estimate construction durations based on their estimated value. These are generally based on medium-sized commercial developments, hospitals or similar public type building for which historical data has been collected and take little account of the specific complexity. Clearly it is evident that the use of the value/time principle based a medium rise office building in Kuala Lumpur would bear little significance to a hydro-electric plant with mass concrete dam located in primary jungles of Sarawak. Thus in such circumstances any programme would need to be established by using industry production rates and adjusting to reflect the actual circumstances.