A massive part of the management of any construction project consists of checking to make sure what is being built matches the project requirements. This process is known as construction quality management. One of the key ways we manage this process is by completing Inspection and Test Plans. Inspection and Test plans are completed for all major construction activities on a project. An Inspection and Test Plan (or ITP for short) documents everything we are planning on checking and testing to verify what has been constructed matches the project requirements.
ITPs are fundamental to construction quality management and in this short article we’ll cover:
- What inspection and test plans are
- The scope, structure and contents of an ITP
- The process of developing an ITP
- How to complete and close out ITPs
- And go through a brief example of an ITP
What is an Inspection and Test Plan
An inspection and test plan is a document that describes the plan for managing the quality control activities of a work lot. A work lot, in project management, is a component of the overall project scope. So for example, piling would be a work-lot of the construction of a new bridge. Through our ITP, we want to prove that the works covered in each work lot comply with the design and ultimately project requirements for that work lot. ITPs are required for all significant construction activities involving hand-over to the client.
ITPs need to be produced prior to works commencing. They are typically produced by the engineer responsible for the works, but in some instances may be produced by sub-contractors. Following their production, they will then get checked internally by the project quality team before being issued to the client for their review and approval. As the ITP will document the ultimate verification and validation for the works completed, the client will review ITPs very carefully.
The approved ITP will document all the verification and validation activities including test methods, documentation to be provided, any hold or witness points requiring sign off – we will touch on these more later, frequencies of testing and who is responsible for signing off and approving the final ITP.
ITPs need to be completed as works are performed to ensure no testing or verification points are missed. Any failed tests that cannot be rectified easily before works progress will result in a Non-Conformance Report being raised.
So what scope will an ITP cover? An ITP needs to cover each of the individual construction activities identified in the WBS. Each lot will need an inspection and test plan created for it. The scope needs to be clear and definite. All major construction activities that result in something being handed over to the client require an ITP.
Let us now quickly go through some examples of different construction activities we would have an ITP written for and how often we would fill out a new ITP. I will go through some examples of ways I’ve set them up on projects.
For piling, we filled out an ITP for each pile, for conduit install we completed a new ITP for every section of conduit from pit to pit and for concrete works, we completed a new ITP for every concrete pour. Once we go through how to develop an ITP, it may make a bit more sense how often to complete them.
What about activities like traffic management and service proving? Well, typically you would not need ITPs for these as these are activities that facilitate construction works but do not involve the production of a product that is handed over to the client.
So how is an ITP structured? Well, depending on the company you work for, there will be some variety in how they choose to structure their ITP. Basically, an ITP needs to cover the following things for a given scope of works; it needs to sequentially list out all the testing activities that will take place, a reference to the relevant standard or specification that requires this testing activity, the test method that will be used, the timing or frequency of testing, the acceptance criteria, and the responsible person for signing it off.
The test activity will give a description of the work activity to be inspected and tested. What this is will depend on the stage of the construction activity. For example, survey set-out, excavation or during back-filling.
The relevant specification will inform which specification or criteria the activity is being undertaken in accordance with. So, for example, when excavating for electrical conduits, AS3000 specifies that electrical conduits must have a minimum of 500mm cover So the test activity would be excavation and the relevant specification would be AS 3000.
Next, we need to list the test method. This is the method we use to complete the inspection. For example, to verify our trench depth we may measure it with a tape measure. Other types of test methods may include visual inspections or forms of testing.
The timing and frequency section specifies when and how many times the inspection must be carried out for example at 10% complete, every 100m of trenching or maybe every day. Again, this will depend on the activity being undertaken. Additionally, if the ITP is written for a scope of works where there have been lots of errors and NCRs, you may elect to test more frequently.
The verifying record specifies what recorded evidence is required to prove that the inspection and testing has taken place and the outcome of the inspection and testing. So, for our trenching example, we may attach a photo to our ITP of a tape measure in the trench to prove the depth of the excavation. Alternatively, this may not even be required, and we could just tick to say we had indeed inspected the works and verified the trench depth.
Finally, the responsible section nominates all the relevant authorities who need to have inspected and approved the activity. There may be multiple individuals responsible for checking including the sub-contractor, a representative like us from the contractor, the client or even other third parties such as an electrical inspector. In this section, we will also need to nominate if it is a hold point – this means works cannot proceed past this point without the relevant approval. For example, the client may nominate a hold point to inspect the steel re-enforcement prior to any concrete pour. Or it may just be a review point where works can proceed without the responsible person approving them. In between these two is a witness point, where the responsible person needs to be notified but can choose not to attend the inspection when informed and works can proceed.
The contents is the information we will populate the ITP structure with. To begin with, the ITP needs to follow the method statement. This is the methodology used to complete the construction activity. Against, the methodology we need to identify the testing, inspection and records associated with each stage.
In general, any construction activity will follow a methodology. The first step will be a review of the design. We will check the drawings and specifications for errors and constructability issues before issuing them to the sub-contractor.
Next, we need to check that the materials supplied to complete the task are correct. We will check approved materials have been procured, factory testing completed, delivery dockets are provided, any type approvals have been completed, any mock-ups or examples have been approved and that they have been stored correctly.
Next, we will check that the worksite is ready for that construction activity to commence. We will check that any previous trade has completed their works correctly and our works are ready to commence. We will ensure previous trades have completed their QA. This step is critical and has commercial implications. If we tell a trade to start works and a previous trade has not fully completed, then we may be liable for contractual claims if the works were not completed correctly.
We will also need surveyors to mark out the works providing heights, dimensions, and any additional information from the design. It is critical to ensure that works are set out correctly and that the surveyors are using the correct set-out files.
Once all these checks are complete, construction can commence. This will require detailing nay testing and inspection required depending on the construction methodology and relevant specifications. Any hold, witness and inspection points will need to be identified.
When works are complete, there will be checks to make sure any as-built documentation has been collected. Such as survey pickups of points, for example when constructing piles, survey may record top of piles so that this can be provided to the structural steel fabricators.
Additionally, any testing to ensure the works have been completed correctly will be conducted followed by a hand-over to other trades or commissioning.
This is the general methodology used to manage works and will change slightly depending on the works being performed, for example, for electrical works you likely won’t need as much survey input as for civil works, but electrical works may require more checks that the correct materials are being used.
Writing an Inspection and Test Plan
The first step in developing an ITP is to identify and review the key inputs. We will look at the WBS to review what the scope of the work activity we are writing the ITP for must cover. Next, we will look at the methodology for the works. This will be developed in consultation with sub-contractors and workforce during planning. We need to identify all the steps in how the construction activity will be conducted. We will review the design to look to identify all the depths, dimensions, products we have to use, performance requirements and so on. Finally, we need to review any relevant specifications, whether these be client specifications or statutory requirements.
By the end of this stage, we need to have identified all the steps in carrying out the construction activity and all requirements from the design and specifications.
Now we can begin writing our inspection and test plan. Each activity in the method statement, as well as covering all the key points such as design, survey, hand-over from other-trades, material checks and so on we spoke about in the last section, will become our test activities. We can populate these in the left-hand column of the ITP structure.
Next, against each of these activities, we will need to complete the remaining columns of the ITP. So, we’ll need to identify the relevant specification, test method, timing and frequency, acceptance criteria and any hold, witness or inspection points relevant to that test method.
Once this has been completed, we can now get our ITP approved. Firstly, we will submit this to the internal quality team who will do their own checks, ensuring that all the criteria from the design and specifications are documented in the ITP. Once they are happy with the ITP, they will submit it to the client for their review and approval. The client will typically make several comments, usually listed in an excel spreadsheet that you will have to respond to by updating the ITP or proving that the requirement they are asking for is not in fact required. You’ll then need to submit your comments back to them and once this back and forward has been completed, your ITP will be approved, and you’ll be ready to start works.
Make sure you allow enough time for this process to take place. I’ve seen ITPs take up to 6 weeks to get final sign off from the client. Usually, there will be contractual timeframes that the client must respond within. However, depending how long it takes to close out the review comments, the process can be long and unfortunately painful!
Inspection and Test Plans should be in place before any works commence. They then need to be completed progressively as works are completed. There is a tendency for ITPs to be completed after works are completed however this can result in a game of catch up and missing important hold and witness points. Tests may be missed, and important quality issues not identified.
The photo below is from a rail project I worked on. It shows a draw rope that had been installed in a conduit and not spliced together correctly. When the cable haulers were pulling cables, the poorly joined draw ropes kept breaking resulting in the cable haulers having to re-rope the conduits, losing time and money.
ITPs help us to identify issues as they arise when they can be easily resolved ultimately avoiding costly errors and rework. We ensure things like survey set-out are doing correctly and there is a smooth hand-over between trades. Imagine building a concrete plinth and forgetting to get compaction test results? We would either have to wait and see if the plinth starts to sink in the poorly compacted soil and become damaged or jackhammer out the entire plinth and re-compact the ground.
On top of this, the completion of ITPs will have several commercial implications. They can be a useful tool when managing payment of sub-contractors, only paying sub-contractors for the works they have completed and properly close out the QA. ITPs will typically need to all be completed before a contract can be closed out and they can also be a tool for managing defects and back-charging of sub-contractors.
ITPs also support the overall project completions process. The progressive completion and hand-over of quality avoids rushing at the end to sign off all the ITPs at once. They can ensure the client is familiar with the works taking place and any quality issues as they are arising. Ultimately, the progressive completion of QA will avoid any failure to meet practical completion.
Let’s now go through an example process of preparing an ITP, going through the step by step process we identified in the previous section. Developing an ITP involves three steps, firstly, we need to collate all the inputs, next we prepare the ITP and finally we need to get it approved. We are going to run through this example for the installation of a section of underground electrical conduits. You can download the ITP I prepared covering this scope below:
Step 1 to collate all the inputs to the ITP. These are the requirements we need to identify and reflect in our inspection and test plan. The first major requirement we will look at are the design drawings. As an example, design, I’ve done a really quick mock-up of an example design using PowerPoint, although I don’t think I’ll be getting a job as a drafter anytime soon, the simplified mock-up has all the required details from the design.
The design shows a cross section of an electrical trench showing three 100mm electrical conduits surrounded by bedding sand. The conduits are 600mm below finished surface level. 250mm below finished surface level will be marker tape.
Next, we’ll look at any governing specifications. For this exercise, I’ve made up a few example specification requirements we’ll need to follow. We have the below requirements for these works:
- We will need a permit in place to excavate.
- We need to be using approved materials.
- Compaction testing is required.
- And at the completion of the conduit installation, we will need to mandrel test the route as evidence that electrical cable will be able to be pulled through the route. This will be a hold point where the client will need to sign off that the mandrel testing has been completed.
Also, we need to understand our methodology for doing the works. These are the steps we are going to complete the task. For the installation of an underground electrical conduit, we will do the following:
- First, we will excavate the trench
- Second, we will lay the conduit in the trench and glue it together
- Next, we will backfill around the conduits with bedding sand
- Then backfill up to 250mm below finished surface level and lay marker tape
- Finally backfill up to finish surface level and compact
- Finally, we’ll complete compaction testing and mandrel testing to prove the works have been completed correctly
In step 2, we now need to fill out our ITP structure based on what we identified in step 1. I have attached a copy of an example ITP I completed to cover this scope above. I created this ITP using the steps I went through earlier. I began by completing a high-level structure based around the pre-work checks we would need to conduct, procurement of materials, the actual construction activities, any testing, and close-out. Next, I elaborated on the detail under each section.
So for pre-works, we’d need to check the design to make sure the sub-contractor has the right drawings and any approved RFIs or design changes, all applicable permits are in place, the works have been marked out by survey and there has been a structured hand-over from any previous trades. The important, critical activities will be reviewed by a project engineer while the site engineering activities such as survey set-out will be reviewed by the Site Engineer. The Supervisor will check that the work area is clean and been handed over properly from previous trades.
Next, we will make sure all the correct materials have been procured. To install underground electrical conduits we need conduits, marker tape and back-fill material. We will need to ensure all these materials have been approved and are correct and we’ll verify this by collecting any delivery dockets.
Next, we will list out the construction methodology under the construction section and note any checks we need to complete against this. Basically, to install underground conduits, the construction methodology is to trench to the correct depth and width, install conduits, back-fill and compact, install the marker tape and finally install the draw rope. Against each of these items I have listed checks that we will do and evidence that will be recorded. For example, to ensure the trench is dug to the correct dimensions and depth, we will get survey to check the depths prior to conduit installation. To ensure the conduits have been installed correctly we will get a photo of the conduit arrangement every 20m.
Section 4 lists any applicable testing that is required on completion of the works. For our conduit installation, we will complete a mandrel test on completion of the works. Mandrel testing involves pulling a large plastic ball through the conduit to ensure it is free from debris and cables can safely be pulled through the route. As records of this being completed, we will record a video of us completing this test.
Finally, once testing is complete, we will need to complete the activity close-out requirements. This will involve marking up the design with any required design changes. This process is known as red-line mark-ups as well as ensuring the survey and digital engineering team have captured all the as-built data.
Now our ITP has been completed, we’ll now need to submit it for review. The first stage of review will occur internally, when we submit our ITP to senior project engineers and the internal quality team. They’ll complete their own checks to ensure it covers all necessary checks. Once they are happy, it will get submitted to our client. They will complete a thorough review and likely make a number of comments we’ll have to action or prove are not necessary. Any updates to the ITP will be submitted back to the client and this back and forward will continue until all parties are happy with the ITP contents.
If you found this useful, check out the link below to our full Udemy course on construction quality management. We cover everything you need to understand about how construction management professionals verify that what has been built matches the original project requirements: