An "Inspection and Test Plan" (ITP) might also be called a "Quality Inspection Plan".
Inspection and Test Plans set out critical control points or 'hold points' at various stages within a process. Each control point is a scheduled inspection or verification activity where you will make sure that things are progressing as they should be.
Inspection and Test Plans are often used as a way to satisfy the requirements of the ISO 9001 standard related to control of production and service provision.
8.5.1 Control of production and service provision
"... c) the implementation of monitoring and measurement activities at appropriate stages to verify that criteria for control of processes or outputs, and acceptable criteria for products and services, have been met; ..."
8.6 Release of products and services
"The organization shall implement planned arrangements, at appropriate stages, to verify that the product and service requirements have been met. ... "
In ISO9001:2008 version, it was:
8.2 Monitoring and Measurement
"The organisation shall monitor and measure the characteristics of the product to verify that product requirements have been met. This shall be carried out at appropriate stages of the product realisation process in accordance with the planned arrangements (see7.1)."
Did you notice "at appropriate stages"? This means that checking happens throughout the process and not just on the final output. That's a good strategy as the earlier you pick up mistakes or problems, the less it costs you.
There is also a requirement to keep evidence of the check, which means a record of some kind.
What the standard is saying is that you must plan when, and what, and how you will check that your product or service is meeting requirements. Planned and executed properly, an ITP will ensure a consistent output. It's up to you to determine where these appropriate points are in your process. It's also up to you to determine what your records will be.
In general the ITP should follow the sequence of operations and clearly define who is responsible for signing off each check.
First decide when in the process you want to conduct an inspection or check. Common hold points are prior to a phase of high cost/ high value work, where any pre-exisiting problems will create difficulties at the next stage, or will mean a high cost of re-work when discovered later in the process.
For each check point you need to specify exactly what to look for (perhaps refer to another document for details), how the check is recorded, and who must perform/signoff the inspection.
An Inspection and Test Plan is not the same as an Inspection Checklist.
An ITP tells you when in the process to perform an inspection. The details of the inspection are contained in the checklist, and are typically recorded there.
An ITP might refer to different checklists for each inspection point, or could refer to a code or standard that sets out the requirements for what and how the check must be performed, e.g. AS1012 - Methods of Testing Concrete. A simple ITP can closely match the checklist.
The Inspection and Test Plan is like a Work Instruction and the Checklist is a form that becomes the actual record. Both the ITP and Checklist are documents that must be controlled.
A common critical hold point is 'Incoming Goods" - particularly for manufacturers. Before you start working with the raw materials, you want to be sure that the supplier has delivered what you asked for. If the wrong material has been shipped, it's better to send it back at the beginning rather than after you've spent time and money working on it. A minimal inspection in this case would be to examine the supplied Material Certificates.
In construction, an inspection hold point usually comes after significant work as been done and prior to covering it all up in the next stage or work. e.g. prior to internal lining of the walls; prior to tiling going over the waterproofing.
Here's an example ITP:
|Activity||Method||Acceptance Criteria||Record||Inspected By|
|Prestart documentation||Visual Check||Hard copies of documentation in project binder||F-12||Doc Controller|
|Establish Site||Visual Check||Checklist items 1-15 completed||F-34||Site Manager|
|Excavation||Dimensional check||As per site drawing||drawing||Site Manager|
|Pre-pour||Visual Check||Pre-pour checklist, site drawing||F-72||Engineer|
|Foundation pour||Measure||Slump test - 50mm +/- 10mm||Delivery record||Engineer|
|Foundation pour||Strength test||Specification, 30 MPa minimum||NATA lab Test Report||Engineer|
The detailed inspection instructions for each step in this example are contained within separate checklists. e.g. F-12 is a simple list of all the documentation that must be present before the site preparation can commence. The Pre-pour checklist, F-72, includes a space to record any rectification required. Both items are important records for the project and can help to resolve any later disputes.
e.g. Pre-pour Checklist:
|Check Item Description||Who?||Sign||Pass/Fail||Details of Rectification|
|Formwork dimensions check|
|Formwork grade and alignment|
|Forms clean, smooth, watertight|
|Reinforcing steel placed as per drawings|
|Critical cover 30mm at all locations|
|Re-bar tied and supported (chairs) as per plans|
Each checklist will also include a header to collect project information, date, final signoff, and other identifying information.
Another ITP for a welded frame:
|Activity||Inspected By||Method||Acceptance Criteria||Record|
|Check correct material spec, size||Quality Control||Visual Check, Tape measure||As per drawing||Checklist QC-22|
|Check cut lengths||Operator||Tape Measure||+/- 1mm from drawing||Q-22|
|Check hole locations & sizes||Operator||Tape Measure||+/- from drawing||QC-22|
|Final Inspection||Quality Control||Visual check||As per drawing, specs||QC-22|
And a closely matching Checklist:
|Description||Who?||Sign||Pass/Fail||Details of Rectification|
|Check correct material spec, size|
|Check cut lengths|
|Check hole locations & sizes|
What's the difference in the "who" in the plan versus the "who" in the checklist? The plan says which role is responsible for performing the inspection, and the checklist records the actual person who performed the inspection on the day.
For technical production work, the checklist can include values to be measured and the range of accepted values - e.g., for a circuit board assembly:
|Resistors #1-3||110 - 130 ohms|
|Resistors #4-8||200 - 240 ohms|
|Box weight||95g - 105g|
|Display||zero defective pixels|
In this case, the "who" and rectification details are contained in the header and footer sections of the checklist.
qualityinspection.org has a great infographic on Preparing a Quality Inspection Checklist
with some more Examples of inspection checkpoints here.