Leakage prediction for buildings, cases, bags and bottles

Michalski, Stefan

doi:10.1179/sic.1994.39.3.169

Cited by 14 publications

(4 citation statements)

References 5 publications

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“…RH exchange occurs by movement of water vapour via three dominant pathways: through cracks, holes and small openings, through solid walls, or through gaps and larger openings (Thomson 1977;Michalski 1994;Tencer 1994). Low water vapour permeability of plastics used in commercial storage boxes (Begley et al 2008(Begley et al : 1409Maier, Calafut 1998: 4;Barrie 1968: 284;Shashoua 2008: 247) means that the main route for water vapour exchange between the interior of a plastic storage box and its external environment is expected to be through the opening at the box seal (Thickett, Odlyha 2010), driven primarily by differences in water vapour concentrations between the two environments (Burrows et al 2009;Tencer 1994).…”

Section: Variables In Creating a Desiccated Microclimatementioning

confidence: 99%

Desiccated Microclimates for Heritage Metals: Creation and Management

Thunberg

Watkinson

Emmerson

2020

Studies in Conservation

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Since the early 1970s, archaeologists, conservators and curators have turned to published guidance for methods of safeguarding archaeological metals in the short and long term. Much of this has appeared in editions of the ubiquitous handbook First Aid for Finds, the most recent of which dates to 1998. A central message across all guidance has been to dry metals post-excavation and prevent their corrosion during storage by desiccating the environment around them. This has been proven crucial for iron, with reports of catastrophic loss of collections arising from inappropriate storage environments.There has long been agreement that an effective, low cost option for desiccation is the packing of artefacts in boxes with a desiccant. Though advice on the detail of how to achieve this has evolved over time, what has not changed is the lack of quantified evidence for the methods proposed.Informed by a survey of current practice in the sector, this study investigated quantitatively the many variables involved in creating desiccated microclimates for storage of heritage metals. This paper presents the results of an evaluation of the airtightness of a range of commercially available boxes, the optimum mass of desiccant, the effect of external environments, and preliminary data on the efficiency and risk of drying damp objects with silica gel. A second paper will report the effect of stacking boxes on their airtightness and present data on the accuracy and long-term reliability of humidity indicator cards.The guidance arising from laboratory testing of the hardware and methods for desiccated storage is designed to be achievable and adaptable. Combining these findings with corrosion rate data for iron artefacts allows the escalation of risk to objects from decisions in the storage process to be calculated.Together, these papers offer an evidence-based and practice-focused update to First Aid for Finds.

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Section: Variables In Creating a Desiccated Microclimatementioning

confidence: 99%

Desiccated Microclimates for Heritage Metals: Creation and Management

Thunberg

Watkinson

Emmerson

2020

Studies in Conservation

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“…Thomson (1977) developed a model of RH dependence on buffer capacity and case leakage, but the big practical mystery remained: why did cases that were built of the same materials, contained the same buffer, and looked identical leak so very differently? Twenty years later, Michalski (1994a) developed equations for the four leakage mechanisms and confirmed each one experimentally.…”

Section: The Discovery Rejection and Resurgence Of Passive Rh Contrmentioning

confidence: 99%

“…Moving ahead a quarter century, new research by and Michalski (1991Michalski ( , 1993Michalski ( , 1994aMichalski ( , 1994bMichalski ( , 1996 undermined and explained the old "ideal" of 70°F/50% RH and began to explore true safe limits for even very mechanically sensitive objects. To understand the mechanical risks to collections, Mecklenburg and his colleagues used finite element modeling to study component materials of objects (e.g., cottonwood used in a panel painting).…”

Section: Choosing Standards and Best Practices For Environmental Desimentioning

confidence: 99%

“…Red solid lines show data for fresh mammalian teeth, which represent ivory and behave like wood in terms of having different responses across the grain; canines have solid cores and hence are more vulnerable to splitting than molars, which are hollow (Williams 1991). Dotted lines represent three vulnerability classes (very high, high, medium), each one double the vulnerability of the next, defined in Michalski (1996). The dashed black line shows the vulnerability of a mixed collection, which can contain all vulnerability classes, including some objects with no vulnerability.…”

Section: What Is Stable? What Is Safe? What Is Tolerable? the Five Ermentioning

confidence: 99%

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