Inspection and Testing

Inspection and testing required for a project should be indicated in the project quality plan. On a construction site, inspection and testing is carried out at three stages:

  • on receipt of purchased or subcontracted items or service;
  • during a construction process in which an in-process check is conducted before proceeding to the next step;
  • before final delivery or handover of the finished works.

Materials, components and appliances received on site are subject to receiving inspection and/or testing. The amount and nature of checking required vary with the degree of control exercised at the supplier’s premises and the recorded evidence of conformance. Where an incoming item is released for urgent use prior to verification, the location where it is used or installed should be recorded.

During construction, inspection and testing should be carried out progressively to ensure that any defective work is not built upon or covered over. The requirements for in-process inspection and testing are usually documented in the inspection and test plans (ITPs) which form part of the quality plan. An ITP lists in sequence the activities involved in a process, specifies the checks or tests to be performed and the acceptance criteria, indicates the hold points when verification of quality is a prerequisite to continuation of work, and identifies the authority of approval at each hold point. There are many construction and installation processes for which ITPs have to be prepared. Some examples are excavation and earthwork, piling, concreting (including precasting), structural steelwork, brickwork and blockwork, roofing and cladding, plumbing and drainage, installation of mechanical and electrical services.

An inspection plan for submittal to the owner might reasonably be expected to cover all or some of the following items:

  1. Establishment of detailed inspection procedures.
  2. Outline of acceptance/rejection procedures.
  3. Preparation of a chart showing all tests required, when they are needed, the frequency of sampling and testing, the material being tested, and who is obligated to perform the tests.
  4. Establishment of who will be responsible for calling the laboratory for pickup of samples for testing, who will call for special inspectors when needed, and to whom such outside people will be directly responsible on the project.
  5. Identification of who must physically prepare samples for testing, the contractor or the inspector; determination of whether the contractor will provide a laborer to assist the inspector in obtaining samples and transporting samples for testing.
  6. Establishment of ground rules for acceptable timing of work operations after sampling and testing; mandatory scheduling must be provided to assure not only time to make samples and tests, but also time to make corrections needed before work may be allowed to continue.

The Inspection and Test Plan (ITP) is a quality assurance tool commonly used throughout the construction industry. An effective ITP may also aid communications, assist to establish expectations and promote collaborative working in the project team.

An Inspection & Test Plan (ITP) is a document which describes the plan for managing the quality control and assurance of a particular element of the construction works providing information on the requirements, overview of the method(s) to be used, responsibilities of relevant parties, and documentary evidence to be provided to verify compliance.

ITP is a document detailing a systematic approach to testing a system or product (ex. Material, Component, machine, package etc..) through visual inspection, dimensional measurement, Non Destructive Testing, functionality test, factory acceptance test, with the participation of all involved parties. It is used to validate the inspection and test results against design and work specification according to the sequence of operations which are witnessed and verified by the client/owner’s representative hand in hand with the fabricator/constructor.

It is the program of inspection, testing of materials, and survey that shall be prepared and submitted by the contractor to the Client or his Representative for approval before usage and application to the site.

Preparation, Review, Approval and Implementation:

  • ITP and Checklist are prepared and issued by the Quality Engineer
  • Reviewed by the Quality Manager and Construction Manager
  • Approved by the Project Manager
  • Submitted to the Client or his Representative for approval
  • QA/QC Engineer shall maintain a Register of all approved ITPs and Checklists
  • Copy of the approved ITPs and checklists are provided to Quality Inspectors and contractor for implementation

Any activity at any stage of the construction that contributes to quality assurance can be specified within the ITP. For example, an ITP may include an item which specifies that only competent persons are to undertake works and therefore would also summarize how this will be checked (i.e. ‘inspected’) prior to works commencing such as checking and recording qualifications.

Thus, the term ‘inspection’ may not only be a reference to the physical construction works but could be a document, an item of equipment used for the works, a qualification etc. which should be inspected.

Additionally, it is very important that an ITP details the evidence which will be provided to demonstrate the ‘inspection’ or check has been satisfactorily completed and where it will be filed for future reference or collected for inclusion in the building documentation handed over at the end of the project.

In summary, the ITP provides a summary of the what, how, why, when, and who for quality of an element of the works, ex.:

  • What are the requirements?
  • How will compliance of the works be assured? (I.e. what inspection & tests are to be carried out?)
  • How will compliance of the works be demonstrated? (I.e. who will witness and verify the works are compliant? What documentation will be provided to demonstrate compliance for records purposes?)
  • When are inspections and testing required to be completed?
  • Who is responsible for undertaking the inspections and testing?

There are no standard ‘codes’ and organizations usually develop their own preferred method. However, there are some standard accepted types of inspection and test. The following are the most common categories of inspection / test activity. Suggested abbreviations are included in brackets:

  • Witness Point (W) – The activity will be verified by the party / individual in testimony to the satisfactory completion of the item.
  • Inspection (I) – The activity will involve a party or person undertaking a formal verification and recording.
  • Hold Point (H) – The next stage must not commence until the item is completed satisfactorily.
  • Surveillance (S) – A ‘surveillance’ is essentially a mini audit which reviews an aspect of the works in more detail to verify compliance.
  • Audit (AU) –  periodic, independent, and documented examination and verification of activities, records, processes, and other elements of a quality system to determine their conformity with the requirements of a standard.