The Norwich Record Office collects and preserves unique archives relating to the history of Norfolk and makes them accessible across the world.
Run by Norfolk County Council, the record office holds a four star rating. This is the highest available rating as awarded by The National Archives, the official archive and publisher for the UK Government and for England and Wales.
As paper is hygroscopic, it tends to absorb moisture from the air. As a result, air humidification is vital in the preservation of archives.
Rare and historic records, books, maps and the survival of anything paper typically require a relative humidity level of 40-50%rH. As paper reacts to changes in humidity it can become frail. A fluctuation of more than 5%rH is enough to cause irreversible damage.
The Norwich Record Office was using electrode units for its humidification requirements. The units were 20 years old and used a blend of softened and raw water. Michael Lillywhite, director, Independent Humidifier Services Ltd, was asked to inspect the units as part of their maintenance.
Michael comments: “When we removed the mixing taps we discovered the units had been adjusted to be temperature governing and therefore could not get the correct mix. As a result the VAPAC cylinders were lasting a maximum of two months.”
Following a cost saving projection of installing HygroMatik’s FlexLine units versus replacing the VAPAC cylinders, Michael concluded the new units would pay for themselves in seven years based on cylinder savings alone.
Michael adds: “The life expectancy of the cylinder in the FlexLine unit is extremely high and is expected to last 13 years.”
The FlexLine series is HygroMatik’s latest generation of steam humidifier. The units are available as electrode or heater element humidifiers, depending on water quality and desired level of control.
In the instance of the Norwich Record Office, FlexLine heater element humidifiers were selected; the FLH 06 and 09 units, with a respective steam output of 5.5-6.5 kg/h and 8.2-9.8 kg/h replaced the 5 and 9 kg/h VAPAC units.
The FlexLine units were also chosen because of their compact nature. This addressed the tight space issue at the premises as part of the unit had to fit inside an existing external housings to allow the cost to be kept as low as possible.
Michael adds: “As a modular system the flexibility of the FlexLine unit, which includes remote fault and remote on indication, was a significant factor in the specification of the humidifier. The non-contact level sensor in particular stands out as a market leader.
“The life expectancy of the old system was unexceptionable for the customer. The main reasons behind this were the financial and environmental costs of going through so many cylinders. In addition, the old units were rusting through on the drip tray which is not the case with the FlexLine units as they are made from stainless steel. The free training and the support we get from HygroMatik further contributes to our confidence in the units.”