Survey of External Enclosure Performance
Water ingress, Corrosion and Paint Finish of Cabinets and Feeder Pillars Over 20 to 25 years
There are many thousands of Ritherdon cabinets and feeder pillars in service and, stainless steel being highly corrosion-resistant, that number is constantly growing.
There are a few enclosures around the UK which we keep an eye on to monitor their performance as they age. Over the years, this has helped us improve their design and the materials that we use and is the reason why Ritherdon external enclosures are among the highest quality on the market.
This month we did a survey of several local pillars and cabinets to see how some of the old ones are doing but also to test the advice we give that sealing the base of the enclosure prevents internal condensation and mildew on the backboard. It follows on from the article on damp in external enclosures we posted in April 2020.
This report is a photographic summary of what we found.
Table of Contents
Water Ingress Protection
Basic Feeder Pillars - Is it Necessary to Seal the Base?
Plate 1 and 2: R300 Feeder Pillar ~ 10 to 15 years old
It’s probably fair to say that most basic, small feeder pillars (e.g. with just the cut out and protection for a couple of circuits coming out of them) don’t have their bases sealed. In many cases, where the ground water levels are low, this doesn’t cause a problem. The electrical components inside this kind of feeder pillar are perhaps relatively less sensitive to humidity and usually housed within their own sub-enclosure, with an added layer of ingress protection.
Inside the pillar shown in Plate 2 (R300, approximately 10 to 15 years old), with no base seal, the surfaces felt slightly damp and there were some small signs of mildew on the backboard.
Plate 3: R150 Pillar ~10-15 years old
However, the inside of the feeder pillar in Plate 3 (R150, ~10-15 years old, just a few feet above a river) was very wet. There was condensation running down the sides of the enclosure and the backboard was clearly damp, with some mould growing on it. The base was unsealed and, most likely because of the high water-table in that location, there was significant water ingress.
Apart from looking unsightly, the marine grade plywood backboard had still maintained its integrity and felt solid after well over a decade in those conditions. Also, as expected, there were no signs of corrosion on the pillar body either.
Plate 4 and 5: RB460 Metered Pillars ~2 years old
These RB460 cabinets in Plates 4 and 5 had been installed much more recently (probably within one or two years) however the backboard already had a lot of mildew growing on it. The base, while concrete, was not sealed with impervious material (grout or resin) and standing water could be seen in the ducting (Plate 5).
Cabinets with a Sealed Base - Communications Cabinet
When an external enclosure is intended to house more sensitive electrical or electronic equipment it is definitely important to seal the base with an impermeable material. The CP850 cabinet in Plate 6 is based on the RB cabinet range, with the same door sealing design as the RB460 in Plates 4 and 5. The CP850 is a much deeper cabinet and has internal 19” racking installed.
Plate 6: CP850 Cabinet with Sealed Base
The CP850s inspected in this survey all had their bases sealed with resin (and the ducts sealed too).
As a result, the environment inside the enclosures was clearly suitable for the communications equipment they were housing. There was no feel of damp and no sign of mildew on the wooden backboards.
Should we pre-treat the backboards with fungicide?
We decided not to treat the backboards of the enclosures we make for the following three reasons:
- The marine grade plywood boards will maintain their integrity even in very damp conditions for many years (e.g. Plate 3).
- As an ISO 14001 compliant company we aim to minimise our environmental impact. This includes avoiding the use of potentially harmful chemicals wherever we can. Using fungicides in this way would be contrary to that aim.
- Water ingress in any external enclosure is clearly undesirable and so Ritherdon recommend that mildew on the backboard should be a clear indicator to the user that the base needs sealing.
If the cabinet is inspected during a dry period, without this visual indicator, the potential problem might not be so obvious. The integrity of the backboard itself will not be significantly affected by the mildew but the equipment housed in the enclosure may be damaged by the damp.
Older Pillar Performance – Over 20 years old
Some feeder pillars included in this local survey were over 20 years old.
The backboards of these pillars were not inspected this time but Plates 7 and 8 show the condition of the pillars’ exteriors.
Resistance to Corrosion
Plate 7: R150 ~ 20+ years old
Plate 7 shows a Ritherdon R150 feeder pillar, installed at the side of an urban road in the late 1990s. Plate 8 is an R460 pillar of similar age installed by a main road, in a rural environment. Both pillars would have been fabricated from standard 4003 grade stainless steel (some further reading on the predicted service life of different grades of stainless steel from the BSSA).
There was clearly very little corrosion on these 20+ year old feeder pillars, with just some localised staining on bare edges. The powder coating at the base of the R460 has started to peel away in places.
Plate 8: R460 Rural Environment
Durability of the Paint Finish
This pillar was last surveyed in 2012 when the paint was still intact, suggesting that the powder coating will last for at least 15 to 20 years in rural and urban environments. The bare metal exposed by the peeled coating, was still bright and untarnished.
Ritherdon have switched to ‘architectural grade’ powders in recent years, which should last even longer than the coatings on these early pillars.
Conclusions from the Survey of External Enclosure Performance
- Pillars and Cabinets Designed for Water Ingress Protection Ritherdon enclosures are designed to keep water out (IP 24 with louvres, IP 46 without). So, if you see mildew on the backboard then moisture is likely to be coming up though the base.
- Signs of Mildew on Backboard Indicate Water Ingress Rather than treat backboard mildew with fungicide, it is better to stop the water entering the enclosure.
- Seal the Base of Cabinets and Pillars Ritherdon always recommend that you seal the base of your external enclosures. This is a reasonably straight-forward process and can easily be done retrospectively.
- Long Service Life and Performance Ritherdon stainless steel enclosures perform extremely well in typical, roadside environments; maintaining their integrity and functionality, with even the surface powder coating lasting for at least 15 to 20 years.
If you would like any more information on the Ritherdon ranges of external enclosures, see RB Cabinets and for feeder pillars, R Pillars and RH Pillars with hinged doors. For even more cabinets and pillars head to all enclosures. For more detailed information such as data sheets and installation instructions browse the Technical Library or get in touch with the office and we’ll happy to advise.