Using high energy X-ray units or Gamma sources such as Iridium 192, it is possible to carry out detailed inspections of materials to detect metal fatigue or faults in the weld of manufactured components.
Requiring high levels of shielding, these facilities can be rooms or inspection cabinets. The rooms are often large and can accommodate forklift access.
Concrete structures for rooms will be preferred where space permits and will include power operated lead lined doors, with a safety interlocking system. The facility has a separate control room which may require the use of CCTV cameras to monitor procedures.
Cabinets will typically consist of a steel framework clad in lead plywood or interlocking chevron bricks, complete with doors and shielded access points for services.
Additional security arrangements may be required for some radiation sources, e.g. lockable door control panels and additional security locks.
Wardray Premise have provided a complete design, manufacturing and installation service for over 70 years. This has involved all types of shielded enclosures from small inspection boxes and cabinets to free standing rooms complete with totally shielded doors and incorporating cable ducts for all services.
We employ the services of an accredited Radiation Protection Advisor (RPA) who will give advice to ensure that all work meets the current Ionising Radiation Regulations.
Radiation shielding can be accomplished using several types of material. Where space permits, dense concrete structures are cost effective and the incorporation of a maze can reduce the shielding required at an entrance door.
However, the use of lead for x-ray shielding has the distinct advantage where space is at a premium or doors are required.
Lead plywood or interlocking lead chevron bricks also have the advantage of being re-usable when a facility needs to be upgraded or relocated.
Our service also caters for power operation of exceptionally heavy doors, complete with manual override, battery back-up, proximity and movement sensors, all necessary warning lights, interlocks and safety systems.
Please see our Shielding Materials pages for details of the materials we use for radiation shielding.
X-ray and Gamma Shielded RoomsTop
The image on the right shows a typical example of a steel framed freestanding structure forming a room for a 225kV x-ray facility.
The walls and ceiling were clad in interlocking lead chevron bricks, the sliding door being constructed in a similar manner.
The door was power operated with all necessary interlocks and safety systems.
NDT Inspection CabinetsTop
NDT Inspection cabinets provide economical test facilities for small objects. Internal dimensions are governed by the size of the x-ray tube, focal distance required and size of the test object. Access doors, cable ducts and removable service panels can be included without affecting the shielding properties.
This cabinet is a typical example of a unit designed to suit a customer's specific requirements. Manufactured as a steel clad lead lined cabinet for a 150kV x-ray unit, it stands on a 4 tonne scissor lift for accurate height adjustment and has a 500kg motorised drawer allowing easy introduction of items to be x-rayed with a large single door giving access from the side
Power Operated Lead Lined DoorsTop
Included below are some examples of recent contracts for power operated lead lined doors for NDT facilities.
RAS Laffan, QatarTop
A recent contract for The Nakilat Ship Repair Yard, RAS Laffan in Qatar is another illustration of our ability to design, manufacture and commission highly specialised installations, meeting the very specific requirements of our individual clients.
The challenge was to provide the total shielding to the door opening of an external building, built on an area of desert reclaimed from the sea. All exterior surfaces and components are fully protected from damage by salt water and sand.
It initially involved our own Radiation Protection Advisor (RPA) who was commissioned to identify the shielding requirements for this contract, based on the use within the room of a high energy radio-active source of Iridium 192
A pair of doors each 4.6 metres high x 3.6 metres wide were constructed from a steel supporting framework produced in our North of England factory. This accommodated layers of interlocking lead bricks to a total thickness of 80mm. With the external faces and edges clad in steel each door weighed in excess of 22 tonnes!.
As this facility was located in an area with extreme weather conditions, a special purpose paint finish was specified by the client.
Each door was supported on special heavy duty wheel boxes running on a track. This was recessed into a special trench 600mm deep and retained with suitable top supports, all enclosed within a weather proof pelmet.
The doors were power operated by two heavy duty Hydrovane compressors. They were fitted with an emergency backup facility in the event of power failure, complete with all necessary safety systems, warnings lights, and alarms.
The vast size of the structural opening was required to accommodate large haulage vehicles. The size of the floor trench made it necessary to provide heavy duty plates to cover the trench and track. The plates linked to the power operating system automatically raising and lowering them as the doors were opened and closed.
To achieve a total shielding to the opening, linings of lead bricks of a similar thickness to the doors were also fitted to the jambs and head of the structural opening and recessed into the floor.
On completion, our Radiation Protection Advisor (RPA) in conjunction with our Client, conducted the final testing and commissioning of the facility.
This is an example of a purpose built facility at the National Physical Laboratory project in Teddington, UK.
This project involved the construction of 16 power operated lead lined doors complete with safety systems and all necessary interlocks. The shielding ranged from 7.5mm to 160mm of lead, the latter in a door weighing 10 tonnes. Similar lead thicknesses were used to construct ducts to shield apertures for services in the ceiling, all suitably supported in a steel framework.
The contract involved undertaking all necessary calculations of the lead shielding requirements for the doors together with concrete thickness and appropriate densities for the walls and ceilings.
For quotations and advice please provide the following information.
- NDT requirement: e.g. cabinets, doors, enclosures
- Structure, composition and thickness of any walls which may be incorporated within the enclosure.
- Clear opening sizes required for doors.
- Any reports on the specified shielding requirements from your own Radiation Protection Advisor (RPA).
If reports are not available please also provide:
- Details of the radiation source, type and output of the X-ray equipment or Gamma Source.
- All required positions, heights and angles of the radiation source in relation to surrounding walls and ceilings.
- Information on the surrounding area:
- Can access be limited?
- Location of other buildings.
- Can access over roof be limited?
- Location of unclassified personnel.
- Likely workload, type and sizes of test objects.
- Any relevant drawings, site layouts, etc., would be most helpful.