<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-size: 13px;color: rgb(0, 0, 0);font-family: arial, sans-serif;"><style type="text/css"><!-- DIV {margin:0px;} --></style><div style="font-size: 13px;color: rgb(0, 0, 0);font-family: arial, sans-serif;"><div>Some other thoughts on Humidity and temperature as they can have an impact of on your C02 scrubber. <br></div><div><br></div><div>Humidity is probably less important since we a usually operating in wet environments (and we breath out</div><div>moisture), but solutions like Sodasorb require a minimum humidity to start working. I've not seem anything <br></div><div>about to an upper limit to the amount of humidity. <br></div><div><br></div><div>Temperature is probably more relevant since we may operate in environments that can get cold, and at</div><div>lower temperatures CO2 absorber can stop working . The Johnson Sea Link fatalities where due to</div><div>low temperatures reducing the effectiveness of the CO2 absorber.</div><div><br></div><div>Although I may consider adding temperature sensor to the scrubber rather than measuring the air</div><div>temperature so it can account for heat from exothermic reactions.</div><div><br></div><div>Cheers,</div><div> Ian.<br></div><br><blockquote style="padding-left: 5px; margin-left: 0px; border-left: #0000ff 2px solid; font-weight: normal; font-style: normal; text-decoration: none; font-size: 10pt; font-family: arial,sans-serif; color: black;">-----Original Message-----
<br>From: "Sean T. Stevenson via Personal_Submersibles" <personal_submersibles@psubs.org>
<br>Sent: Dec 13, 2020 10:08 AM
<br>To: personal_submersibles@psubs.org
<br>Subject: Re: [PSUBS-MAILIST] Life Support Alarms
<br><br>There is a humidity guideline in the ABS rules, which is 30% - 70% RH (non-condensing). While cabin temperature is not specifically addressed in the underwater systems rules, it is addressed elsewhere in ABS publications. I don't remember offhand whether it is from the ergonomics guide, the bridge design guide, or the steel vessel rules, but I do recall that HVAC is to maintain temperature within the range of 14°C to 30°C (57.2°F to 86°F). PSubs may need some leeway on the low end, substituting appropriate clothing (and emergency / survival insulation) for active heaters. Diving bells carry emergency insulating survival cocoons for the occupants for an emergency which entails loss of hot water supply to the bell, as the temperature will rapidly drop to the ambient water temperature. PSubs are no different unless they are insulated by design.<br><br>Sean<br><br><br>-------- Original Message --------<br>On Dec. 13, 2020, 10:42, Jon Wallace via Personal_Submersibles < personal_submersibles@psubs.org> wrote:<blockquote class="protonmail_quote"><br><div class="yahoo-style-wrap" style="font-family:times new roman, new york, times, serif;font-size:16px;"><div dir="ltr" data-setdir="false">I'm looking to start a discussion to create a PSUBS standard for max/min cabin operating conditions. I'm not convinced temp or humidity matter all that much overall and require an agreement. I would start with the following:</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">O2: 19.0 to 23 percent</div><div dir="ltr" data-setdir="false">CO2: 0 to 5000 ppm</div><div dir="ltr" data-setdir="false">Pressure: +/- 1psi</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Comments?</div></div></blockquote></personal_submersibles@psubs.org></blockquote></div></div></body></html>