LOB was first applied to industrial manufacturing and production control, where the objective was to attain or evaluate a production line flow rate of finished products.
The basic concepts of LOB have been applied in the construction industry as a planning and scheduling method. Several attempts either to modify the basic LOB technique or to develop variations named differently have also been made.
The line-of-balance technique is based on the underlying assumption that the rate of production for an activity is uniform. In other words, the production rate of an activity is linear where time is plotted on one axis, usually horizontal, and units or stages of an activity on the vertical axis. The production rate of an activity is the slope of the production line and is expressed in terms of units per time.
Examples of the variations include;
Velocity diagrams - (Roech 1972),
Construction planning technique (CPT) - (Peer and Selinger 1973),
Vertical production method (VPM) - (O'Brien 1975),
Linear scheduling method (LSM) - (Johnston 1981),
Time space scheduling method (TSSM) - (Stradal and Cacha 1982),
Repetitive project model (RPM) - (Reda 1990).
P3.3.
When operating as a company keeping track of costs is a very important part of a business if the business is to survive. If costs are not monitored it may result in wastage of funds or even bankruptcy. A technique that can be used to help businesses foresee what the future cost may be is known as estimating.
Estimated cost.
This is how much a company estimates a project will cost them. This is worked out the budget stage of a contract when the company normally employs an estimator or quantity surveyor to work out how much capital is needed to complete a project. They will also have to take into account the level of overheads such as salaries for head office staff, heating and lighting costs, rates and insurance. Overall estimated cost is defined as how much a project is expected to cost from start to finish including areas such as wastage, site losses and plant hire.
Actual cost.
This is the total figure that has been spent on completing the project. It would be nearly impossible for a company to be able to estimate the exact amount that a project would cost from start to finish, mainly because of unexpected and unseen costs that appear during the duration of the project. These can include theft from site, vandalism, wastage and also building errors were somebody has taken the wrong measurements from a drawing on site and extra work may be required to rectify the problem at a cost. Also if an estimator or quantity surveyor makes a mistake when calculating the estimated cost this could cause the project to run heavily over budget meaning the company may be working at a loss.
Cost planning.
Cost control is the process of keeping track of all of the overall profit and loss that is occurring on a site. This can also be implemented prior to a contract starting and is normally completed once the budget and estimated cost has been calculated.
A popular method of cost control is working out monthly profit and loss and reporting this at a monthly cost meeting.
Cash Flow.
Once this has been done Cash flow can be predicted and a build forecast programme produced. Cash flow is the movement of money in and out of a business and is achieved by studying the rate of expenditure required to finance the construction of a project and comparing it with the rate that income is received. This can be recorded using charts, graphs and tables and is often shown at a monthly cost meeting.
Monitoring of construction and installation work.
A vital part of any construction project is the monitoring of construction and installation works whether it is going to be carried out by the in house operatives or external contractors.
Once the works required have been identified a works order can be raised or a specification can be put together so that the works can be put out to tender and the contract awarded to the most suitable contractor, sub contractor or specialist contractor dependant on the works.
All works must be supervised through to completion this can be done by carrying out various site visits to check on progress and quality of workmanship, or for larger projects this can also be done by holding regular site meetings. Monitoring can be carried out by a number of people within a company such as the clerk of works, building surveyor or site foreman.
When works are completed these can be post inspected to make sure that the works and materials are to an acceptable standard, any variation or omissions can be agreed there and then on site and if there is further works to be done or recalls for any reason these can be agreed there and then on site. Post inspections dependant on the works can be done with a representative of the contractor before payment is made.
On Costs.
On costs are the costs that are necessarily incurred in the general day to day running of a business.
These will include items such as,
- Office, yard rent and rates.
- Office salaries and expenses
- Advertising
- Interest on borrowed capital
The other items that a business will need to take into consideration include the direct & indirect costs.
Direct Costs these will include items such as,
- Weekly Wage
- Probable Overtime
- Percentage to attract labour
In-direct Costs these will include items such as,
- Sick pay
- Public Holidays with pay
- Annual Holidays
- Inclement weather payments
- Employer’s National Insurance contribution
- Training levies
- Redundancy Payments
- Employer’s liability and third party insurance
Overheads can either be fixed or variable. When they are calculated they will look at the cost of indirect charges & on-costs and work out the expenditure on these items. When these amounts have been calculated it is then possible to work out the gross annual turnover of work.
The costs of overheads will also then be calculated to enable a calculation to be made to work out the percentage of overheads to estimated turnover of work.
Fixed overheads will include items such as;
- Office Salaries
- Rents and rates
- Electricity and fuel costs
Variable overheads will include items such as;
- Interest on borrowed capital
- Salaries on principals.
P3.4.
There are various methods used to plan, schedule and manage the supply and utilisation of resources, viz materials, plant and labour/sub-contractors. Different types of companies may use different methods for controlling this and it can vary depending on the size of the company and also the type of work and contract that is being undertaken.
Materials.
Materials Management takes up a great amount of time as without the materials no works can start. There is a vast amount and types of material available and these must be purchased and delivered as the requirements set out in the drawings to allow the project to be completed as per the client’s instructions.
Before works start on site samples of some of the materials will need to be submitted to both the architect and structural engineer so that hey can determine the suitability of the material for the specific job, and that when it is used in the way in which it was intended it conforms to the standard regulations, this is known as quality control.
The submitting of materials for approval can sometimes mean that the developer may have to liase with the Local Council for their approval before planning permission is granted. This is to ensure that the style of brick and tile suits those of others buildings within the surrounding area.
When the materials have been approved and before the actual orders have been placed the scheduling process must take place, this is where the buyers who are working for the developer must measure the quantities required from the working drawings supplied, this way it helps to reduce wastage and loss. Once all of the quantities have been measured the schedules can be sent to the suppliers for them to provide quotations for the project.
When approved quotations are received the orders can be placed with the relevant suppliers this will take into consideration three important factors Quality, Price and Availability. For items that are ordered in bulk, these orders are normally placed in advance of work commencing on site and will normally be set up so that the site manager can call materials off as and when they are needed.
When orders have been placed it is the responsibility of the site manager to ensure that enough materials are kept on site to supply operational needs, enough storage space is available to accommodate these materials and that materials are only called off when they are needed because the longer they are stored on site, the more likely they are to be stolen or damaged.
The site manager may have to deal with various issues on site regarding the management of materials this will include waste control, loss prevention and stock control. Two common causes of waste include damaged materials being able to be used and excess materials not being utilised. Loss prevention methods include
checking deliveries are not short, controlling vandalism on site and also reducing the risk of theft on site by ensuring all materials are in a secure place where possible. Methods of stock control can include monthly stock sheets, checking the materials on site against delivery tickets and checking for any damaged materials when a delivery is made.
If there are any surplus materials left over at the end of a project they are normally transferred to another ongoing site where they can be re-utilised.
Labour.
There are two main types of labour that can be provided by subcontractor’s dependant on the type of project or works that are to be carried out this will include the following;
Labour only.
This is basically providing the labour for certain works required using the materials that are already provided on the site such as timber, bricks, blocks, kitchens and appliances.
The most common trade that is used labour only on sites is bricklayers this is because the bricks, blocks and mortar will already be on the site as they would have been previously been approved.
It is important when using labour only that the quality of work and the amount of worked produced is checked continuously throughout the project.
Labour and Materials.
This is providing the labour and the materials that are required to not only provide the labour to complete a job but also supply the materials needed for the work.
Dependant on the type of works the developer may invite companies to tender for different works and provide quotations. When selecting a labour and materials sub contractor there are a number of different aspects to take into account when selecting a company for a job these will include price, previous quality of work, reputation and experience.
It is important that wastage is monitored with labour and materials subcontractors as they can be wasteful with materials if they know they will be paid for it regardless of the amount used.
It is important that subcontractors are monitored and supervised at all times this can be done using a time sheet to monitor that they are not charging for more hours than they have been on site for.
Plant.
On sites companies either own items of plant or they hire them.
There are various aspects that must be taken into consideration when a decision is to be made whether to hire or purchase an item of plant. This will include the plant being hired and the timescale it is required for also the cost difference for both hired and purchased items must be calculated.
For a number of different types of works that are to be carried out, if the labour employed is labour and materials it may mean that no plant will have to be hired or purchased as the plant will be in with the price supplied by the sub-contractor. This will include items of plant such as excavators, bulldozers and cranes.
If a forklift truck is required permanently on site then a cost analysis to determine whether it would be more beneficial to hire or purchase the plant must be carried out by the site manager as he controls all plant on site. If items are hired and left standing on site this means that money will be wasted, items of plant must only be hired when needed and returned as soon as they are finished with.
This is usually done by the site manager who would develop a schedule and record to show when items are likely to be needed on site and also how long they are on site for. It is important that plant is maintained properly when on site and a site manager is expected to keep records for this and allow them to be inspected when requested.
Below I have completed a cost analysis for an excavator to show if it would be more cost effective to hire or purchase.
Excavator – Time required on site: 60 weeks (continuous)
Cost to Hire.
Transport Cost = £180 each way (£360)
Hire Rate = £460/week including driver and maintenance. (£27,600)
Fuel Cost = £80/week (£4,800)
Total Cost = £32,760.
Cost to Purchase – Life Expectancy: 5 years.
Purchase Price = £34,000 less re-sale value £24,000 (£10,000)
Maintenance = £50/week (£3,000)
Wages for Driver = £260/week (£15,600)
Fuel Cost = £80/week (£4,800)
Interest on Loan = £5000
Total Cost = £38,400.
From the above calculations above I have found that it is more cost effective to hire the excavator in this case because it is £5,640 cheaper to hire than to purchase.
P3.5.
Health and safety is a major issue within the construction industry, regulations are constantly being improved and updated to ensure that construction sites are safer places to work.
Health and safety issues can be raised on sites through the induction pack that is given to new employees and throughout the site by using signs and notices. The main worry to construction companies is the safety and welfare of site workers, accidents on a construction site can also delay production if a site has to be temporarily closed down due to an accident occurring on site while an investigation is carried out. It is in a company’s best interest to make sure adequate health and safety measures are in place to prevent accidents occurring.
Below are various preventative measures that are used to manage safety for various items on a construction site.
Fire and Fire Fighting.
Employers have legal duties in respect of fire safety; the most relevant to this are the Health and Safety at Work etc Act 1974 Sections 2 and 3 and also the Management of Health and Safety at Work Regulations, 1992 sections 3 and 4. These require employers to ensure, as far as is reasonably practicable, the health, safety and welfare of employees and others affected by their work activities. In order to achieve this, they must carry out and record suitable and sufficient risk assessments, then implement the control measures necessary to ensure an acceptable level of safety.
To ensure that fires on site can be dealt with effectively the main forms of fire prevention on a site should include;
Training - All members of staff should be given training in the emergency response procedures for the site. This will include training such as;
- Induction training, this training should commence on the first day of employment so that employees are familiar with the basic procedures.
- Regular ongoing fire safety awareness training, instruction or training in what to do in case of fire.
- Specific fire safety management training, additional training may be required particularly for supervisors and managers with special duties in the event of fire.
Daily Checks – This will include the daily checks that should be made of the fire safety equipment, this should include,
- All escape routes, including passageways, corridors and external routes are clear of any obstruction, free from slipping or trip hazard and available for use.
- All fastenings on doors along escape routes operate freely so that they can be opened quickly in case of emergency.
- That all doors on escape routes open freely.
- All exit and directional signs are in place and unobstructed.
- All fire extinguishers are in position, have not been discharged and have not suffered any obvious damage.
Designated assembly points – This is where all workers on site should evacuate to should a fire break out.
Fire Extinguishers – These should be allocated around the site and accessible to workers. As an addition to this a fire point should also be set-up where a fire bucket and fire blanket should be made accessible.
All of the above measures should be supported by sufficient signage on site.
Liquefied Petroleum Gas
Various forms of gas may be used on a construction site such as butane and propane for gas heaters and cookers and also oxygen and acetylene may be used which is used to cut metals.
All forms of gas are stored in pressurised steel cylinders and should be stored in an appropriate place, normally a steel gas cage. This cage should be kept away from areas of heat and naked flames.
Power Tools
On site there are a number of various trades and they all have various different power tools. The correct measures must be put in place to ensure they are used safely, as they can pose a high risk to operatives and also people working in close proximity.
Most hand-held power tools are operated by electricity or compressed air either to rotate the tool or drive it by percussion. Some of these tools are also designed to act as rotary / percussion tools. Generally the pneumatic tools are used for the heavier work and have the advantage that they will not burn out if a rotary tool stalls under load. Electrically driven tools are however relatively quiet since there is no exhaust noise and can be used in confined spaces because there are no exhaust fumes.
Safety can be managed by using PPE, this will be supplied by the employer and must be worn where appropriate, this should include items such as ear defenders, safety goggles, gloves and face masks. In some cases specialist power tools may require additional items of PPE, an example of this could be
Safety is also managed by following relevant regulations. The regulation that covers the use of power tools is the Health and Safety at Work Act 1974, this details what can be done to control health and safety, it can be divided into;
Employee’s duties.
- To take reasonable care for the health and safety of himself and of other persons who may be affected by his acts or omissions at work; and
- As regards any duty or requirement imposed on his employer or any other person by or under any of the relevant statutory provisions, to co-operate with him so far as is necessary to enable that duty or requirement to be performed or complied with.
- Duty not to interfere with or misuse things provided pursuant to certain provisions.
- No person shall intentionally or recklessly interfere with or misuse anything provided in the interests of health, safety or welfare in pursuance of any of the relevant statutory provisions.
Employers Duties.
- It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees.
- The provision and maintenance of plant and systems of work that are, so far as is reasonably practicable, safe and without risks to health;
- So far as is reasonably practicable as regards any place of work under the employer's control, the maintenance of it in a condition that is safe and without risks to health and the provision and maintenance of means of access to and egress from it that are safe and without such risks;
The provision and maintenance of a working environment for his employees that is, so far as is reasonably practicable, safe, without risks to health, and adequate as regards facilities and arrangements for their welfare at work.
For the use of power tools risk assessment may be done, please see below for an example taken from my workplace.
RISK ASSESSMENT - Power Tools.
TASK: The use of power-operated tools.
WORKFORCE: Multi Workforce.
PERSONAL CAPABILITIES: Only persons trained and certified are allowed to use certain power tools these are; Cartridge Operated Tools, Portable woodworking Power Tools, Changing Abrasive wheels.
EQUIPMENT: Personal Protective Equipment; Goggles or face visor, ear defenders.
Residual Risk Rating: Likelihood x Severity = Risk Rating (ref Corporate procedure.
Next Review Date: June 2009
___________________________(Print Name)
____________________________(Signature)
Manual Lifting.
More than a third of all over three-day injuries reported each year to the HSE and local authorities are caused by manual handling. Manual handling means the transportation or supporting of a load by hand or bodily force, and embraces lifting, lowering, pushing, pulling, carrying or moving. Injury may result from the weight, shape, size, external state, rigidity or lack of rigidity of a load, or movement of its content.
Manual lifting is an important area to be covered in safety management on site as many workers sustain back injuries on construction sites every year caused by not lifting materials and equipment properly. To avoid the need for manual handling operations involving a risk of injury, must include a sufficient assessment of manual handling operations which cannot be avoided.
Injuries from manual handling operations could include cuts and bruises, sprains and strains, particularly of the back, amputations and fractures, plus chronic cumulative problems.
The Manual handling operations regulations have been brought into place this includes duties for;
Employers.
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Avoid – The need for hazardous manual handling, so far as is reasonably practicable.
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Assess – The risk of injury from any hazardous manual handling that cant be avoided.
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Reduce – The risk of injury from hazardous manual handling, so far as is reasonably practicable.
Employees.
- Follow appropriate systems of work laid down for their safety.
- Make proper use of equipment provided for their safety.
- Co-operate with their employer on health and safety matters.
- Inform the employer if they identify hazardous handling activities.
- Take care to ensure that their activities do not put others at risk.
Vehicles and Plant
A construction site may require various vehicles and plant such as forklift trucks and excavators. These should only be operated by suitably qualified and trained individuals this can be done by utilising the CSCS card system.
The CSCS was set up to help the construction industry to improve quality and reduce accidents. CSCS cards cover hundreds of occupations and are increasingly demanded as proof of occupational competence by contractors, public and private clients and others.
The CSCS card gives employers an effective way of identifying skilled and experienced professionals. Maybe that's why thousands of companies have taken up the scheme since 1995.
Today more and more contracting clients are demanding CSCS approved operatives; this is so that companies can protect both their reputation and their bottom line by insisting their workforce carry CSCS cards.
CSCS recognises the abilities of skilled professionals; the CSCS card serves as protection for future employment. The more and more employers that adopt the scheme, the CSCS card will become an industry standard.
The suitably qualified person should produce their licence before operating the machinery on site. All vehicles and plant items should be checked on a weekly basis by a qualified and competent person and these records should be kept and be available for inspection when required.
P3.6.
On site communications are essential; it helps to continue the flow of information throughout all parties working on a project, it can help to prevent any problems that may arise with the daily running of the project and if any problems do arise they can be sorted out straight away as regular contact can be made to solve the problem.
Employees that are involved with the different aspects of a project and are required to liase and communicate with each other on a regular basis, the best way to do this would be through meetings whether it is a weekly progress meeting or a tool box talk. These meetings can be used to discuss various aspects on a site such as material requirements, performance of contractors or sub-contactors and also any technical issues such as kitchen and bathroom plans.
The size of the company and the site may determine the levels of contact between various parties. The company where that I work for HomeZone Living is a small social landlord in comparison and there are a number of different teams that make up the company. The director and the team manager have regular contact with various members of staff including the Assistant and Area Property Surveyors, the operatives, the various office staff and the subcontractors. This allows them to keep their ear to the ground and find out what is happening at every stage of the business.
With large companies the Managing Director is unlikely get involved at ground level of a project this is because the company structure would be completely different.
Communication and liaison activity would be used before a project starts during the design and planning phase, would be ongoing during the construction phase of a project and would also be required after a project is completed. A prime example of communication during a project is regular site meetings. Various members of a project team would be required to attend site meetings, sometimes together and sometimes on separate occasions.
Minutes.
Minutes are usually taken at meetings, this is done so that there is evidence of what was discussed or agreed for future reference. Copies of the minutes are usually forwarded to all parties for reference.
During a site meeting one person may be allocated the duty of taking minutes or alternatively each individual may take their own. Minutes are a form of note taking and for example may be taken at a monthly site meeting. These minutes would include any issues, problems, ideas and other information that arises at the meeting.
The main people that would normally be required to attend a site meeting would be the client, the architect/engineer, contractor and main sub-contactor. When toolbox talks are carried out the main people required to attend will be operatives, supervisors and maybe clerks of works.
Below I have detailed the advantages and the disadvantages of using minutes in meetings;
Advantages.
- They are a good way of making sure any good ideas raised are recorded and not forgotten about.
- It allows all members to discuss any issues or problems with other parties and members of the teams.
- A way of keeping a checklist for each member of the team to do tasks they have been asked to do.
- If somebody is asked to carryout a task during a meeting, the minutes can be used as a way of checking that they have done this.
Disadvantages.
- If the minutes are not taken properly they may be hard to understand and follow.
- Urgent tasks that were asked to be done at the last meeting, they can be reminded about, or the progress of these can be monitored.
- Any issues that may have been raised at the last meeting, these can be looked at again to find out if they have been rectified. This could be a disadvantage to the person who should have carried out the task because if it has not been done it will have been noted on the minutes and brought up at the next meeting.
CONCLUSION :
This assignment has given me greater knowledge into how techniques and practices are used in the planning and controlling of a building site, I found the use of the string diagram interesting as it allows you to carryout desk top studies into the requirements of a site without physically being there.
It has also allowed me to research into the financial side of running a site such as estimated costs and cash flow, I have also been able to use the experience that I have gained whilst at work to write about the monitoring of construction and installation works, and the various processes that go with it.
I have detailed information on the various standards and statutory compliance that can be achieved in relation to various items and I have also used an example of a Risk Assessment on Power Tools used from HomeZone Living.
BIBLIOGRAPHY :
- Class Handouts, Management Principles & Application - Meadowbank Educational Services 2002.
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Information on CSCS cards obtained from
- Infromation relating to Homezone Living taken from my own experiences.
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Precedence networks from
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Manual Lifting information obtained from HSE
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CSCS
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Information and example of Gantt chart obtained from
- Fire and Fire Fighting information obtained from the Health and Safety at Work etc Act 1974 Sections 2 and 3 and also the Management of Health and Safety at Work Regulations, 1992 sections 3 and 4
