Hacker News Reader

Comment by chris_st | Hacker News Reader

From Glowforge's website, for their base model:

> It needs ventilation via the provided 4″ diameter (10.2cm) hose. We recommend putting the hose out a window.

They also say:

> Lasers normally require some ventilation via a small tube out a nearby window. Our optional Air Filter that sits under Glowforge and ventilates using HEPA filters and charcoal, meaning no outside ventilation is required.

Best to my knowledge HEPA and charcoal don't help against CO. So running one with the filter in an unventilated space might still be hazardous.

"To qualify as HEPA by US government standards, an air filter must remove (from the air that passes through) 99.97% of particles that have a size of 0.3 µm."

Carbon monoxide is a few orders of magnitude too small to be caught by a HEPA filter, in fact a filter that could filter CO would filter oxygen and nitrogen as well. Such a filter would just be a pump.

There, however, exists a patent for a filter for CO, it works by converting the CO to CO2: https://www.google.com/patents/US5564065

It is possibly to filter gases of similar molecular weight. https://en.wikipedia.org/wiki/Membrane_gas_separation

This technique is routinely used to generate concentrated supplies of oxygen or nitrogen, but is wildly expensive compared to ventilation.

Needing to eliminate CO is an old, well-solved problem. Even the cheapest catalytic converter would do so.

(It's not quite as simple as just putting one in-line with the waste gas flow- the catalyst would also need to be externally heated.)

I'm guessing this is undergoing a hurried rewrite, to add something along the lines of 'or you may die.' they're gonna get sued out the yin-yang for this even if the dead couple totally ignored the instructions, on the grounds that the instructions didn't state the danger clearly enough.

Having said that, while good safety information is important, two MIT-trained engineers should really have known better.

Why should they have known better? He was a software engineer and she may have had exposure to lab technique but a Glowforge doesn't scream "needs an industrial hood" or anything. Yes, they clearly _could_ have known better, but 'should' seems to be making too-strong assumptions about their class work, MIT or other. They could have had economics degrees for all we know (less likely given their careers, but you get my point).

Yeah, while I get that the general public misses this, I'm surprised to see people who apparently think that "engineer" means a Star Trek-style omnicompetent generalist.

I dunno man, if something says you need to ventilate it by putting an exhaust hose outside, I figure there must be a good reason for that. I have a lot of hazardous chemicals in my house because I paint and a lot of artist paints have toxic ingredients. I read the safety warnings carefully even though I know little of chemistry.

It says you don't need to vent if you use the filter.

I read the safety notices that manufacturers affix to their products and take them at face value unless I have reason to believe otherwise. It seems kinda stupid not to.

And it said you don't need to vent if you use the filter.

Glowforge company is upthread, says the deceased were not customers of theres. Presumably it's a different brand of laser cutter.

That said, I'm assuming Glowforge is going to scramble to make sure that users use their device safely regardless.

... while all their marketing materials and videos show Glowforge sitting happily in the middle of a living room with absolutely no exhaust pipe.

I think the bigger issues is that these kinds of DIY maker tools are marketed as in-home. You wouldn't put a band saw in your spare bedroom-why do people use these kinds of tools in a normal house/apartment? Though two engineers living in Berkeley are probably not going to have a garage, alas.

Reply on news.ycombinator.com