oven ventilation requirements

We are installing a new reflow oven and I have been told that we do not need to vent the exhaust out through the roof since we have a false ceiling. All that is required is to vent above the false ceiling and that the air exchange is great enough that we do not need to go further. My question is primarily is it SAFE as far as the particulates and fumes are concerned? The paste formulations we use are 96.5SN/3.5AG and 95SN/5AG. thanks

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| We are installing a new reflow oven and I have been told that we do not need to vent the exhaust out through the roof since we have a false ceiling. All that is required is to vent above the false ceiling and that the air exchange is great enough that we do not need to go further. My question is primarily is it SAFE as far as the particulates and fumes are concerned? The paste formulations we use are 96.5SN/3.5AG and 95SN/5AG. | thanks | Must have been a manager or an accountant. Is it safe? Probably not. Is it legal? Probably not. You might get away with a very small oven, a very large over ceiling area with great ventilation. The fumes are likely to infiltrate the return air ducting of your HVAC and be distributed over the plant. Particulates fall and most false ceilings like T-bar will let it right through. I'd bet OSHA would take exception to this practice (it only takes one disgruntled employee - read big $) and it's just bad practice. Doesn't the oven need an exhaust fan anyway? The only savings would be the run to the roof. Noisy too. John Thorup

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| We are installing a new reflow oven and I have been told that we do not need to vent the exhaust out through the roof since we have a false ceiling. All that is required is to vent above the false ceiling and that the air exchange is great enough that we do not need to go further. My question is primarily is it SAFE as far as the particulates and fumes are concerned? The paste formulations we use are 96.5SN/3.5AG and 95SN/5AG. | thanks |

Brian,

First off if you don't mind any metal corrosion above your ceiling go ahead! I assume you have A/C and heat that also have ducting up there. You'll probably circulate you fumes everywhere. OSHA probably won't like that. I highly recommend that you at least vent out the side of your building if a hole in the roof is the issue.

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| We are installing a new reflow oven and I have been told that we do not need to vent the exhaust out through the roof since we have a false ceiling. All that is required is to vent above the false ceiling and that the air exchange is great enough that we do not need to go further. My question is primarily is it SAFE as far as the particulates and fumes are concerned? The paste formulations we use are 96.5SN/3.5AG and 95SN/5AG. | thanks | Brian, We had the same claim years ago at another shop. We didn't even vent to a false ceiling, just out into the plant. The managers were not going to allow another hole in the roof unless we could prove we needed it! Had the OSHA people come in and check us, found no reason to vent outside. However it was a singe reflow oven, in a large well vented shop, not a lot of production volume. It may rest less on technical requirements and more on distraction factors to employees (read how bad it stinks).

Boca

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| We are installing a new reflow oven and I have been told that we do not need to vent the exhaust out through the roof since we have a false ceiling. All that is required is to vent above the false ceiling and that the air exchange is great enough that we do not need to go further. My question is primarily is it SAFE as far as the particulates and fumes are concerned? The paste formulations we use are 96.5SN/3.5AG and 95SN/5AG. | thanks | Brian: I understand that your concern is safety and that you've received several responses along that line. There is usually two reasons for this question.

1 Don't want to make / too cheap to make / didn't budget for roof cut and plumbing. SOLUTION: Too bad, suck-it up and protect the troops that make things happen. 2 Can't make roof cut because landlord would hurt someone / building layout will not allow it. SOLUTION: Buy in-building air filtration system. It will end-up costing about the same amount of money as a roof cut over 5 years, you can take it with you when you leave, and move it when you re-arrange the furnature.

my2�

Dave F

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| | We are installing a new reflow oven and I have been told that we do not need to vent the exhaust out through the roof since we have a false ceiling. All that is required is to vent above the false ceiling and that the air exchange is great enough that we do not need to go further. My question is primarily is it SAFE as far as the particulates and fumes are concerned? The paste formulations we use are 96.5SN/3.5AG and 95SN/5AG. | | thanks | | | Brian, | We had the same claim years ago at another shop. We didn't even vent to a false ceiling, just out into the plant. The managers were not going to allow another hole in the roof unless we could prove we needed it! Had the OSHA people come in and check us, found no reason to vent outside. However it was a singe reflow oven, in a large well vented shop, not a lot of production volume. It may rest less on technical requirements and more on distraction factors to employees (read how bad it stinks). | | Boca | | | For me it�s a hot subject, although I had an exhaust for the whole reflowunit the radial cooling fans blew out the stuff and that�s not chanel No5. Besides, cleaning was one of the most hated jobs in PM. It is said that there is no known risk for human health but one of my best workers started suffering from allergy getting asthma attacks. She was checked for month until they found the cause, it was solder steam she reacted at. We lost her and her lungs are irreversibly damaged. Although it wasn�t only in our place were she was exposed to that stuff I feel sorry for her and I try now to eliminate all sort of things that possibly cause any harm to anybody even if it�s said there is no risk with it. I personally quit a new job in a place where I saw that there�s no chance for me to improve things because of the slaveholderlike managment.

That�s my opinion, experience, advice

Wolfgang

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