International Labor Organization handbook is designed to help provide information and training for inspectors. It contains information on key safety and health concepts and occupational safety and health issues, including managing an inspection program and performing on-site inspections.
Section 2: Key OSH and construction concepts
Understanding and using the main OSH and construction terms and concepts will facilitate proper communication among all those involved in the construction process.
Although many of the terms have been defined in different documents, some terms are sometimes used with different meanings, and different terms are sometimes used with the same meaning.
To avoid misunderstandings, we set out below some of the key terms used in both areas and define them as they will be used in this document.
They are organized, as far as possible, into “pairs” of similar terms and definitions.
The main terms and concepts related to OSH used here come from laws, regulations, standards, guidelines, specifications and other documents. The most important ones are defined below, including some notes.
Incident (ILO-OSH 2001): An unsafe occurrence arising out of or in the course of work where no personal injury is caused.
Accident: The same than an incident, but where the unsafe occurrence causes a personal injury.
Note: The terms “incident” and “accident” do have a broader definition, but here they refer to occupational safety and health. For the specific purposes of national law, these definitions may vary from country to country.
Competent person (ILO-OSH 2001): A person with suitable training, and sufficient knowledge, experience and skill, for the performance of the specific work.
Note: This concept refers to a physical person. A “competent legal person” should include one or more “competent physical persons” besides other requirements usually defined by law.
Document (ANSI Z10): Written, electronic, or photographic information such as a procedure or record.
Audit (ILO-OSH 2001): A systematic, independent and documented process for obtaining evidence and evaluating it objectively to determine the extent to which defined criteria are fulfilled. This does not necessarily mean an independent external audit (an auditor or auditors from outside the organization).
Inspection: Similar to an audit, but focusing on a single item or process and based usually on “yes/no” answers, whereas audits are more detailed and look at the entire process in depth.
Note: Audits may also review all elements that can influence each of the processes under consideration. They may go beyond “yes/no” answers, e.g. to determine how far an item or process complies with a reference document (law, internal specification, standard, etc.) and how it can improve. An audit may involve many specific inspections. Where these inspections cover all the single processes of a chain of a broad process, then it may work like an audit.
Hazard (ILO-OSH 2001): The inherent potential to cause injury or damage to people's health.
Risk (ILO-OSH 2001): A combination of the likelihood of an occurrence of a hazardous event and the severity of injury or damage to the health of people caused by this event.
Note: Different scales may be used to determine the risk level (RL) of any construction process, depending on the classification of the likelihood (Lk) and of the severity (Sv) to be considered. In this document a scale of 1 to 5 (Figure 1) is used for both likelihood and severity (very low, low, medium, high and very high) and the risk level is calculated using the following formula:
Risk Level (RL) = Likelihood (1<=Lk<=5) x Severity (1<=Sv<=5)
The result may be grouped into five risk level intervals: RL<5 (Very Low), 5<=RL<10 (Low), 10=<RL<15 (Medium), 15<=RL<20 (High) and 20<=RL<25 (very high)
|Very Low||Low||Medium||High||Very High|
Figure 1 – Example of a risk scale (likelihood x severity)
Hazard assessment (ILO-OSH 2001): A systematic evaluation of hazards.
Risk assessment (ILO-OSH 2001): The process of evaluating the risks to safety and health arising from hazards at work.
Note: In this document, whereas “assessment” is taken as subjective, “evaluation” is quantitative.
Active monitoring (ILO-OSH 2001): the ongoing activities which check that hazard and risk preventive and protective measures, as well as the arrangements to implement the OSH management system, conform to defined criteria.
Reactive monitoring (ILO-OSH 2001): Checks that failures in the hazard and risk prevention and protection control measures, and the OSH management system, as demonstrated by the occurrence of injuries, ill health, diseases and incidents, are identified and acted upon.
Note: In this document, more emphasis is given to the active monitoring rather than to the reactive monitoring. A proactive approach for OSH should take priority over the reactive approach.
Compliance (ANSI Z10): Meeting the requirements of local, state or federal statutes, standards or regulations.
Conformance (ANSI Z10): Meeting the requirements of the organization’s OHS-MS and this standard.
Note: Whereas “compliance” refers to compulsory requirements, “conformance” refers to voluntary requirements.
A construction project usually involves many parties. The main ones are the owner (client), the designer and the constructor. Each of these may involve other further parts (subcontractors, workers, etc.) and be organised in various forms. They may be a physical or legal person, public or private. Other interested parties may include financial bodies, insurance companies, end-users, supervisors, official inspectors, quality controllers and safety experts.
The development of a construction project draws on many concepts during its life cycle and these should be clarified in relation to the parties. The specific OSH duties of each of them should be set out clearly.
Some of the most frequently used terms in a construction project shall be clarified, bearing in mind that, sometimes, different meanings are assigned to the same terms for reasons such as the legislation applicable to the construction industry in a specific country. Different meanings in different languages have also caused misunderstandings among construction experts from different countries.
Construction (ILO Convention C167): this term covers: (i) building, including excavation and the construction, structural alteration, renovation, repair, maintenance (including cleaning and painting) and demolition of all types of buildings or structures; (ii) civil engineering, including excavation and the construction, structural alteration, repair, maintenance and demolition of, for example, airports, docks, harbours, inland waterways, dams, river and avalanche and sea defence works, roads and highways, railways, bridges, tunnels, viaducts and works related to the provision of services such as communications, drainage, sewerage, water and energy supplies; (iii) the erection and dismantling of prefabricated buildings and structures, as well as the manufacturing of prefabricated elements on the construction site.
Construction site (ILO Convention C167): any site at which any of the processes or operations of a construction (as defined above) are carried on.
Workplace (ILO Convention C167): means all places where workers need to be or to go by reason of their work and which are under the control of an employer.
Note: In some countries, a construction site may also be any place where the construction works (as defined below) are carried on, including the places (temporary or mobile) where support activities are carried on.
Construction work: any work for the physical realization, partial or whole, of a new facility (e.g. a building, a bridge, a road, etc.), as well as rehabilitation, adaptation or any other work on an existing facility where it has by law to be carried out by a competent (qualified/certified) person; where the construction work is to be carried out in parts (e.g. the structure, the water system, the electrical system, etc.) and each part is done under a different contract, simultaneously or successively, these parts are usually called a construction job (Figure 2).
Note: A construction work may also be defined as an unique process, consisting of a set of coordinated and controlled activities with start and finish dates, undertaken to achieve an objective conforming to specific requirements, including the constraints of available resources (adapted from the ISO 9000:2005 on the fundamentals and vocabulary).
Construction project: an investment programme to carry out one or more construction works (facilities), where the social, economic, technological and administrative issues, during the whole life cycle are taken into account (Figure 2).
Figure 2 - Construction project, construction work and construction job concepts
Constructor: a competent person, physical or legal, holding official qualification/certification under national law to undertake construction works.
Note: This official qualification/certification, usually, lists the specific works that the constructor may perform; different names are used with the same meaning such as construction company and construction enterprise.
Contractor (ILO-OSH 2001): a person or an organization providing services to an employer at the employer's worksite in accordance with agreed specifications, terms and conditions.
Notes: (i) in the construction industry, a contractor may also be defined as a person, physical or legal, engaged to perform a specific job or service on the basis of a fee (hourly based or task performed based); (ii) besides the constructor and sub-constructors (both are also contractors), many different contractors and/or subcontractors such as enterprises of temporary workers, enterprises supplying construction equipment with operator, self-employed workers, persons (physical or legal) rendering specific services (e.g. OSH experts) may be involved in a construction project; (iii) in many countries, the term “contractor” is used for the purpose of some laws to mean the “constructor” as defined above; (iv) in some countries, the OSH law defines “contractor” as any person (including the owner/client and the principal contractor as defined hereafter), who carries out or manages construction work.
Principal Contractor (adapted from the ILO Convention C167): a person, physical or legal, with actual control over or primary responsibility for overall construction site activities, who is responsible for co-ordinating the prescribed safety and health measures and for ensuring compliance with such measures. When he is not present at site he shall nominate a competent person or body at the site with the authority and means necessary to ensure on his behalf co-ordination and compliance with these measures. The principal contractor should be appointed (usually by the owner/client) whenever two or more employers undertake activities simultaneously at one construction site.
Notes: (i) The principal contractor is not necessarily the general (or main) contractor, but he may be if he is present on site; (ii) The owner/client may act as the principal contractor where there is no general contractor and if he has the knowledge, competence and means to do so under the national law.
Employer (ILO-OSH 2001): Any physical or legal person that employs one or more workers; the constructors, sub-constructors, contractors and subcontractors, while legal persons are also Employers.
Notes: (i) A construction project (execution phase) may involve one constructor (alone or in a consortium, in a joint venture or in another form for a particular project) or more than one constructor (each with a contract with the owner/client); each of these may be helped by sub-constructors and/or subcontractors to perform the construction project, including their subsequent and successive chain of sub-constructors or subcontractors (Figure 3); (ii) concerning OSH, and for monitoring purposes, it is important to distinguish between the sub-constructors (those who are qualified/certified and know the construction job, the risks involved and the prevention measures to implement) and the subcontractors that are not qualified/certified under the national law to undertake construction works; (iii) for OSH monitoring, the self-employed workers should be considered as subcontractors or as any other worker involved in the construction project, as they are involved in the construction project under the control and coordination of whoever engaged them.
Life cycle of a construction project: The set of the main phases in developing a construction project, from the initial idea (identification of the need) to the end of its life (demolition or deconstruction).
Note: These phases may be simplified into the following three: (i) conception and design; (ii) construction/execution, and; (iii) operation/utilization. However, in many cases and depending on the purposes, there is a need to consider more detailed phases such as the following (Figure 4 below): (i) inception, strategic planning, initial studies, feasibility studies; (ii) programming, briefing, planning; (iii) engineering, design; (iv) build, construction, execution; (v) commissioning, start-up; (vi) operation, utilization/use; (vii) maintenance, rehabilitation, adaptive reuse; (viii) deconstruction, recycling, demolition. Depending on each cases, other phases are also considered at different moments during the life cycle, as is the case of “procurement” (designers, constructors, supervisors, safety and health coordinators, etc.).
Project Management (PM): the management, during most of the earlier phases of the life cycle, of the development of a construction project, from inception (including planning, design, procurement, where applicable, etc.) to the end of the execution phase and the commissioning/star-up and, sometimes, including also the “period of warranty” (usually, 5 to 10 years from the completion of the execution phase, largely depending on the legislation of each country). For each construction project, the scope of the PM is clarified in the contract between the parties involved (owner/client and project manager).
Construction Management (CM): the management during only the execution phase, and sometimes also the contractor procurement phase (it does not usually include the conception/design phase). For each construction project, the scope of the CM is clarified in the contract between the parties involved (owner and construction manager).
Construction Management versus Project Management: in both cases, the managers could be the owner’s in-house personnel if the owner has such capabilities, but often they are external experts (individual persons or organizations who act on behalf of the owner/client). In some cases (e.g. European Union Directive 92/57/EEC on safety and health in construction), these managers are also called “project supervisors” and are responsible for supervising the design and/or the execution of the project. When their responsibilities are restricted to the design phase, they are usually called “project supervisors for the design phase/stage” and when their responsibilities are restricted to the execution phase they are usually called “project supervisors for the execution (or construction) phase/stage”. In a CM approach, the construction manager, acting on behalf of the owner/client, has the primary duty of overseeing (and ensuring the accomplishment of) the contracts established between the owner/client and the various contractors. In many cases, they do not participate in the formulation of these contracts and have no responsibility for the quality of the design documents. They supervise the construction of the project based on the owner’s requirements included in the contract with the contractors. If the requirements are not appropriate or the design documents are poor, the construction manager usually has a reduced responsibility on the quality of the final product. If this condition exists, it may be more difficult for the project execution to be successful and the objectives defined by the owner/client may also be more difficult to be achieved. On the other hand, in a PM approach the project manager will be responsible for the entire process, including design document approval and the supervision of the contract documents with the contractors. In this case, the construction project has a greater probability of being successful, depending on the commitment and the skill of the project management team, of the design team and of the contractor team (staff personnel, subcontractors, workers). In some cases, the PM approach is also complemented with a CM team under the responsibility of the project manager.
Construction Management Systems/Models (CMS): the various models to promote the construction project from inception (identification of the need/idea) to the end of its life. The main Construction Management Systems/Models are:
(i) “Design-Bid-Build (DBB)”, in which the owner assigns the design and the execution of the project in two separated contracts, respectively, to a designer and to a constructor (or a group of constructors), respectively; this traditional approach is the most common model in small and medium construction projects (private and public) and sometimes also in large projects.
(ii) “Design-Build (DB)”, in which most of the design and of the execution of the construction project is assigned to the same constructor (or a group of constructors) in a single contract. This model is based on the specifications prepared by the owner (or by another person under his responsibility), which include preliminary designs. The majority of the (detailed) design is the responsibility of the constructor, who usually assigns this task to a designer through a private subcontract. This model is used particularly in construction projects in which, for example, cost and time/schedule savings are expected as a result of technological processes and innovative methods that the constructor may use.
(iii) “Developer-constructor”, in which the developer and constructor are the same private entity, i.e., the developer is both the owner and the constructor. The design is usually assigned to a designer through a private contract. This model is used mainly in residential construction projects.
(iv) “Public-private partnership (PPP)”, a contractual arrangement between a public and a private entity (or group of entities), in which a much greater emphasis is put on whole life cycle performance in order to optimize cost, time, quality, environment and safety and health throughout the construction project. There are many different approaches for the PPP model, depending on who takes the responsibilities and risks during the life cycle of the project (e.g. conception, design, building, operation, maintenance and finance). This model is used mainly in very large and/or complex projects (namely infrastructures, like bridges, motorways, hospitals, etc.), involving a large number of parties (and consequently, many contracts) who share the responsibilities and risks of the project to the extent specified in the contract; some of the most common used PPP approaches follow. Note, however, that the DBB and the DB models referred to above, are also particular cases of PPP models when the owner is a public entity which keeps the main responsibilities relating to the construction project (financing, use, operation and maintenance).
(iv.1) “Design-build-operate-maintain (DBOM)”, also known as “build--operate--transfer (BOT)” or “turnkey”, combines the design-build (DB) model with the operation and maintenance that the owner/client assigns to another entity (or a group of entities), usually private, for a fixed number of years after the completion of the project (usually, between 5 to 20 years, sometimes even more). At the end, the project is transferred to the owner/client. In this model the owner/client is responsible for financing the project, including the operation and maintenance costs, and keeps the revenue from its operation. All the costs are included in the procurement process and so the other entity should stipulate the construction process to be used and provide a detailed maintenance plan.
(iv.2) “Design-build-finance-operate (DBFO)”, also known as “concession”, where designing (majority/detail design), building, operating and financing are transferred by the owner/client to another entity or group of entities (the “concessionaire”), usually private, that assumes all the responsibilities and risks specified in the contract. In this model, the financing may be supplied partially or wholly by the owner through grants and/or through the future revenue originated by the operation (e.g. tolls) for a fixed number of years after the completion of the project (usually, more than 20 years, sometimes called the “concession period”), and ending with the transfer of the project to the owner/client. Sometimes, the owner/client may transfer revenue-collecting of an existing project to the “concessionaire”, together with the responsibility for maintenance.
(iv.3) “Design-build-own-operate (DBOO)”, also known as just “build-own-operate (BOO)”, in which a public entity grants to a private entity (or group of entities) the right to develop, finance, design, build, own, operate and maintain the project in perpetuity. The public entity usually stipulates the general specifications to be followed by the private entity, which becomes the owner of the project taking on all the risks but also all of the surplus operating revenue. This model has been used in special cases, sometimes arising from a private initiative (hospitals, bridges, etc.).