Visual and infrared (IR) inspections are often necessary in areas with limited access and space, or in close contact with objects, especially to avoid high heat levels.
This can be to investigate fire conditions during suppression or overhaul, and inspections of faults or overheating of mechanical and electrical equipment.
When working in tight spaces, follow standard practices to ensure safety.
When working near heat, machinery, and equipment, it’s essential to use the correct personal protective clothing/equipment (PPC/PPE) and to isolate electrical, mechanical, and other services as required.
For areas classified as a “confined space”, procedures and requirements as designated must also be followed.
Visual inspections can occur in places where access is restricted or limited, including, but not limited to, chimneys, vent openings, ceilings, sub-floor, building cavities, behind fixed objects such as machinery, and in or near other equipment.
These limitations can be overcome using various visual equipment, such as mirrors, inspection cameras, or borescopes.
Another method is taking a digital photo or video for later viewing on a camera or smartphone screen, away from the confined space.
Similar to visual limitations, access can also be restricted when using a Thermal Imaging Camera (TIC).
This could be the inability to align the camera with the object of interest to achieve a perpendicular or best viewing angle, or the ability to position yourself to view the screen clearly when the camera is in position.
TICs used in a confined area may require the camera to be very close to the object to be viewed.
The fixed focal range of the camera may also need to be considered.
Objects closer than around 81cm (32 inches) may be out of focus.
To achieve a better view with the TIC, consider moving or removing items, or opening up the area to gain better access and space.
This may be difficult, take considerable time, or result in unnecessary damage and disruption.
If available, a small or compact camera may be easier to use when space is limited, and a camera with a wide field of view may also be an advantage as it can examine a larger area.
Several methods can be considered to improve effectiveness and efficiency when using the camera in restricted spaces.
Some of these include:
The screens of most handheld TICs are usually angled slightly upwards at around 10°.
This is for ease of viewing when holding the camera below the eye-line.
That being the case when we view something horizontally with the camera overhead the TICs screen will be angled above your line of sight.
Simply turning and holding the camera upside down may angle the screen to improve screen alignment if the camera is positioned overhead.
Some TICs can “freeze” the image or record digital still images or video with viewing or playback on the screen.
This provides a simple and effective option that can be used for several applications when the camera can be aligned with the object of interest or target, but the screen is difficult to view due to a lack of space or even where screen glare is a problem.
The “image freeze” function allows a screen capture button to be pressed when the camera is aimed at the area of interest.
The feature “freezes” the image on the screen while the button remains depressed.
The camera can then be re-positioned to view the captured screen image before releasing the button.
For cameras that have an image or video record feature and on-screen playback, captured images or video may be able to be displayed again on the viewing screen by using the camera’s menu selection.
Some cameras have a video transmission capability and provision for remote viewing.
Several cameras have provision for a standard camera tripod mount with 1/4″-20 thread, these can also be utilised for use over extended periods for ongoing video recording and transmission if available.
If the TIC is not capable of capturing images or video, we may be able to capture a visual image of the TIC screen display using a digital photo camera, or smartphone and then view the recorded image or video on the camera or smartphone screen.
Any recorded images or video can also be used for post-incident investigations or after-action reviews.
Just as we can use an inspection mirror to reflect a visual image, they can also be effective in reflecting IR energy.
Mirrors can include purpose-built items for fire service use such as a chimney mirror or a small telescopic inspection mirror available from automotive parts and hardware stores.
We may be able to view the reflected IR energy at a distance so that the image is in focus.
We can also ensure that we are at a safe distance with the camera from hazards.
A comparison can also be done in the visual as well as IR.
If a mirror is unavailable, other smooth, highly reflective materials can serve as ‘thermal mirrors’.
This could include stainless steel or other highly polished metal or glass for example.
While most shiny surfaces will reflect IR, the more suitable the surface the better the image quality will be.
The main disadvantage of reflecting IR energy to the camera is ensuring the alignment of all objects, or the reflected IR image may be too small to view clearly if the mirror is a long distance from the target and the potential for some loss of detected energy when compared to using the camera directly.
In some instances, we may also be able to identify reflected IR energy from fixed surfaces, such as the rear and sides of equipment cabinets.
This may be suitable for the initial viewing to identify anomalies for further investigation or an option when space is restricted for other methods to be used.
Reflecting the viewing screen display with a mirror:
Similarly to how we reflect IR energy to the camera’s sensor, a mirror can also be used to reflect the camera’s visual screen display.
If the camera can be aligned with the object of interest but you are unable to see the screen you may be able to use an inspection mirror to reflect the screen display.
As with other methods, it’s important to ensure that the camera is at a suitable distance from the target so the image is in focus.
As with any reflected view, the image is reversed, and the method requires the alignment of both the TIC and the mirror with the target.
Certain helmet-mounted cameras can be detached and used independently while keeping the In Mask Display (IMD) in place and connected wirelessly.
This can allow flexibility in viewing where space is limited or to view from a protected position.
Other removable helmet-mounted cameras that have a screen on a flexible stalk may also provide possibilities for viewing as previously covered.
The TIC can be used to assist in size-up, equipment inspections, the evaluation of fire spread, and ensuring extinguishment is complete.
The options covered for the cameras used in a tight space may assist the user in maintaining a safe distance and gaining a view of objects of interest where access is limited and can be practiced during training.
Although these options are useful, it’s important to complement them with traditional methods to ensure thorough inspections and complete extinguishment.
Never rely totally on the camera, use it only as another tool to assist you in standard practices and procedures.
Ensure you are familiar with the TIC you are using, including any additional features and functions.
Gavin Parker commenced a full-time firefighting career in 1995. He has undertaken studies on two occasions in the USA and Canada. The most recent was an Emergency Services Foundation (ESF) scholarship. The views expressed are those of the author. Contact: gparker@dcsi.net.au
