With the restrictions around the third lockdown beginning to ease, many industrial archaeology and heritage museums, sites, and societies are planning their re-opening strategies. There’s lots to consider, from volunteer support, and safe forms of working in the field, to making sure that exhibits and buildings are not damaged by adaption to COVID-19 compliant measures.
Historic England have been issuing COVID-19 guidance regularly over the last 12 months. Their latest advice deals with the impact of humidity on the interiors of historic buildings. Adjusting relative humidity to prevent COVID-19 spread could pose long-term damage to heritage interiors. Following news reports on the spread of the virus and lack of advice on disinfecting historic surfaces, Historic England rapidly developed guidance to provide this information. Relative Humidity (RH) and temperature are closely related, but for the temperature range which is found in heritage interiors RH had the greater impact on virus persistence. Relative humidity is the amount of water vapour held in the air at a given temperature, relative to the maximum amount of water that it could hold at the same temperature (expressed as a percentage, with 100% being saturation).
Bodies such as the English Heritage Trust and The National Trust recommend a target RH in their properties of between 50-65%. Below 50% there is the risk of shrinkage and desiccation in wood and glues. Above 65% RH there is a risk of promoting mould growth with an increased risk of mould-related diseases. Anything outside of this range would result in a risk either to visitors or occupants from mould or to the property from mould, desiccation or condensation. Therefore, monitoring and managing RH and temperature at appropriate levels is essential. This is usually achieved through heating and dehumidifiers.
Over winter and into spring 2020/21 concerns were raised that the prevailing weather conditions had increased the risk of transmission of COVID-19; lower temperatures, low RH, and the reduced ultraviolet light from sunlight enhance survival of the virus. With lower temperatures the use of comfort heating in occupied buildings comes into play, but this can drive the RH down. Research indicated that the virus was deactivated at high levels of humidity, but serious concerns were raised in heritage bodies that this would lead to changes in environmental management: turning off dehumidifiers could have devastating effects on many heritage materials. Fortunately for the heritage sector, the RH levels considered appropriate for heritage materials (50-65%) lie within those which effectively reduce the persistence of the viral particles (about 60%).
Further details can be found on the Historic England website here: Effects of Relative Humidity on COVID-19 in Heritage Interiors | Historic England
Council for British Archaeology
As Covid-19 restrictions begin to lift around the UK, many archaeology groups and societies are beginning to look at ways to restart activities such as fieldwork and thinking about developing new event programmes. The Council for British Archaeology (CBA) have updated their COVID-19 advice regarding fieldwork.
At present CBA are unable to provide specific guidance relating to returning to archaeological activities and events as the situation across the UK continues to remain complex and evolving. However, CBA are continuing to monitor government guidance, and their rolling Recharging British Archaeology project is helping to better understand the needs of local groups and how the CBA may be able to help such groups become stronger and more resilient for the future. The CBA are also working with several other organisations to look at ways to provide some more bespoke information to help you with your planning.
In the meantime the CBA’s advice remains that groups and societies should follow the UK Government 5 step guide to working safely, which is a good starting point when thinking about any activities and events you are considering. The 5 steps are:
1. Carry out a Covid-19 risk assessment
2. Develop cleaning, handwashing, and hygiene procedures
3. Help people to work from home
4. Maintain 2m social distancing, where possible
5. Where people cannot be 2m apart, manage the transmission risk
Further details can be found on the CBA site here: Council for British Archaeology | Returning to activities following Covid-19 (archaeologyuk.org)