Up a bit, left a bit, down a bit, right a bitIn researching the previous blog Some dos and don'ts we discovered to our irritation that the main guidance on strongroom atmospheric conditions available to all record repositories including and especially places of deposit for Public Records is inconsistent.
A typical storage environment: Sheffield City Archives
Regarding temperature, BS5454:2000 specifies 13C to 16C with a tolerance of 1C on either side for little used material (7.3.2) or 16C to 19C with a tolerance of 1C on either side for frequently handled material ((7.3.1).
Regarding relative humidity, BS5454:2000 specifies a fixed point between 45% and 60% with a tolerance of 5% on either side (7.3.3) or 40% if little used. Importantly, BS5454 states rapid changes should be avoided.
In each case, BS5454:2000 allows for acclimatisation and avoidance of rapid changes.
However, the National Archives' guidance for places of deposit for Public Records, National Archives Standard for Record Repositories (2004) (pp.14-15) (previously Beyond the PRO (p.11)) appears to differ.
The new TNA guidance specifies different atomspheric environments according to whether a storage building was equipped prior to the publication of BS4354:2000 or for a new building or new equipment, in each case enlarging on BS5454. This difference or variation is admitted by the authors of TNA's new standard. Section 5.1.1 states: although most of the recommendations...are directly based on BS 5454, they should not be taken as a substitute for the fuller range of specifications given in that Standard.
For modern storage areas or new equipment, TNA recommends a constant temperature of between 16C and 19C with a tolerance of 1C either side and constant RH in the range 45-60% with a tolerance of 5%.
For older storage areas specified before BS5454:2000 TNA accepts a constant temperature of between 13C and 18C and a constant RH between 55% and 65%.
So are we due for a new edition of BS5454? We wonder how planners of new repositories fare with these anomalous guidelines. Which ones do they present to architects? If presented with both, what would architects make of them?
It is particularly worrying that BS5454 is clearly invoked by TNA in connection with their approval of repositories under the new National Archives Standard, see their Approved repositories page.
Many heads of repository seeking approval may well be asking which figures to go by and who knows best on this point, the British Standards Institute or TNA?
The matter of atmospheric controls appears to be up in the air, shall we say.