Dear Stephan,
Thank you very much for your detailed explanation and the references. I realize my question may not have been precise enough. I understand that, in theory, effectiveness mainly depends on tightness and the ability to maintain the target oxygen level. What I am actually trying to clarify is the operational robustness of the system itself. In your experience, when comparing: – sealed flexible chambers flushed with nitrogen and monitored over time (with corrective intervention if needed), versus – a fully dynamic system with continuous active gas supply and regulation, do you consider both approaches equally reliable in practice? Specifically, are there noticeable differences in: – stability of very low O₂ levels over several weeks, – frequency of corrective actions, – overall control of parameters (O₂, temperature, RH)? I am trying to understand whether the difference is mainly technical in principle, or whether it translates into meaningful operational differences in real conditions. Many thanks again for your insights. Best regards, Marion Le vendredi 20 février 2026 à 16:21:48 UTC+1, [email protected] a écrit : > Dear Marion, > > > > it is basically a question of the tightness of the system and the desired > duration (in days) for the reduction and hold of the residual oxygen value. > > > > If you have 12-15 m3 heat-sealed barrier film chambers, you either need a > large amount of oxygen absorbers (e.g. ZerO2 absorbers) or a sufficiently > powerful nitrogen generator with adjustable purity for the oxygen value. > > The lower the purity of the nitrogen generator, the longer it takes to > reduce the residual oxygen content from 20.9% to below minimum 1% or a > maximum of 0.5%, depending of the temperature. > > > > - In order to maintain a residual oxygen value of 0.5% over 21 days at > 24°C (current datas from Germany see > https://opac.dbu.de/ab/DBU-Abschlussbericht-AZ-31865.pdf), the chamber > with oxygen absorbers must either be very well sealed or a nitrogen > generator is required to compensate for any leaks. > - The climate in the chamber can be actively stabilized using a dryer > or humidifier controlled by an external control system, or passively using > silica gel pads or other buffer materials. It should be noted that the > objects are acclimatized to the climate in the chamber prior to treatment > in order to prevent increased release of material moisture. > > > > Further information on the subject of anoxia can be found with pictures of > chambers or more literature at > https://museumsschaedlinge.de/anoxia-sauerstoffentzug/ and also at > https://museumpests.net/solutions/ > > > > Best Stephan > > > > Stephan Biebl > > Dipl.-Ing (FH) Holztechnik > > Sachverständiger für Museumsschädlinge (BVFS) > > > > Mariabrunnweg 15 > > D-83671 Benediktbeuern > > Tel. 08857-697040 > > [email protected] > > *www.museumsschaedlinge.de <http://www.museumsschaedlinge.de/> * > > > > > > https://www.instagram.com/museumsschaedlinge/ > > > > *Von:* 'Marion BILLOT' via MuseumPests <[email protected]> > *Gesendet:* Freitag, 20. Februar 2026 15:47 > *An:* [email protected] > *Betreff:* [PestList] Question – Reliability of semi-dynamic nitrogen > anoxia systems > > > > Dear colleagues, > > I would greatly appreciate your feedback on a nitrogen anoxia setup that > could be described as “semi-dynamic”, that is not a fully centralized > continuous dynamic chamber, but not a simple static system either (with > oxygen absorbers). > > The configuration consists of flexible, heat-sealed plastic chambers > (approx. 12–15 m³ each). Each chamber is flushed with nitrogen using a > generator to reach a target O₂ level (reported 0.5–0.7%, but in theory > below 0.1%), then sealed and monitored for approximately four weeks, with > parameter checks and corrective intervention if needed. > > My main question is: In your experience, is this type of setup reliably > effective in practice? In particular regarding: > > - Maintaining very low oxygen levels over time (micro-leaks, drift, > frequency of re-injection, etc.) > - Control and stability of temperature and relative humidity inside > the chamber (homogeneity, condensation risks, issues with dense or large > loads) > > If you have practical experience to share (monitoring protocols, sensor > types, frequency of checks, common failure points, acceptance thresholds), > I would be very grateful. > > Thank you in advance for your insights. > > Best regards, > > Marion Billot > > > > Marion BILLOT > Collaboratrice support scientifique > Invertébrés > T. +41 22 418 6459 <+41%2022%20418%2064%2059> > [email protected] > > Muséum d'histoire naturelle (MHN) > Département de la culture et de la transition numérique > Route de Malagnou 1 > 1208 Genève > www.museum-geneve.ch > > Notre environnement est fragile, merci de n'imprimer ce message qu'en cas > de nécessité. > > > > -- > This PestList and the MuseumPests.com web site are made possible due to > the talent, intelligence, devotion and donations of hundreds of volunteers. > Your donation to help this resource continue would be greatly appreciated. > > Please consider a donation donating at https://givebutter.com/MuseumPests > > To unsubscribe from this group, send email to > [email protected] > --- > You received this message because you are subscribed to the Google Groups > "MuseumPests" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/pestlist/ZR0P278MB107548D45599FD005A854A85ED68A%40ZR0P278MB1075.CHEP278.PROD.OUTLOOK.COM > > <https://groups.google.com/d/msgid/pestlist/ZR0P278MB107548D45599FD005A854A85ED68A%40ZR0P278MB1075.CHEP278.PROD.OUTLOOK.COM?utm_medium=email&utm_source=footer> > . > -- This PestList and the MuseumPests.com web site are made possible due to the talent, intelligence, devotion and donations of hundreds of volunteers. Your donation to help this resource continue would be greatly appreciated. Please consider a donation donating at https://givebutter.com/MuseumPests To unsubscribe from this group, send email to [email protected] --- You received this message because you are subscribed to the Google Groups "MuseumPests" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/pestlist/24d9ebbb-1e9f-4ef1-88f3-8e9ce6ed80e2n%40googlegroups.com.
