2019 Woodshop Dust Collection Vote

History

Announced: January 3, 2019
Language Locked: January 17, 2019
Vote: January 29, 2019

Background

In 2014, PS:1 purchased a ClearView cyclone dust collector (DC) for the Woodshop area. The vote and details of this can be found at: https://wiki.pumpingstationone.org/Wood_Shop_Dust_Collection.

Since 2014 PS:1's membership has increased substantially, and the Woodshop remains one of the most heavily used areas of PS:1. Some of the dustiest machinery in the shop (sanding equipment particularly) have not been connected to this system, and there is not adequate suction at farther machinery to collect dust effectively. As such, the current DC system has proven to be inadequate for current use.

A good reference for the dust collection theory discussed below can be found in Woodshop Dust Control by Sandor Nagyszalanczy.

General Motivation

Sawdust is a well-known respiratory irritant. A summary of health risks posed by sawdust can be found at https://en.wikipedia.org/wiki/Sawdust#Health_hazards. OSHA's permissible exposure limit (PEL) is 15 mg/m3 over 8 hours. In addition, general cleanliness around the Woodshop helps members have space to work on and store their projects, as well as reduce the extra cleaning time more diligent members have to spend to use machinery.

Current Situation

The dust meter in Hot Metals has frequently been read far above the OSHA PEL- for members who use Hot Metals and the Woodshop frequently, the current DC system is allowing an unhealthy amount of dust to remain suspended in the air. In addition any non-HEPA dust collector will not filter very fine particles that can still enter the air. Without proper air filtration fine dust will still be an issue in the shop.

In addition, many complaints have been brought up from members alleging other members are not cleaning tools after using, or sweeping the floor. Blast gates are often not opened or left open, hindering the efficacy of the DC to collect what dust it can collect. Given the ever-increasing membership of PS:1, it is likely that unintentional negligence will continue, and willing members have to spend extra time at the space cleaning sawdust up. Sawdust also often drifts into Hot Metals, becoming a potential fire hazard without extra cleaning.

Often when used the current DC is left on when not needed, left on overnight, or other power-consuming situations.

Lastly, sawdust obscures items on shelves, and reduces the usable space of areas without extra cleaning. Especially in hard-to-reach areas substantial layers of sawdust have settled and are re-suspended when bumped.

In addition, the current dust collector is very loud due to incomplete soundproofing in the closet and ductwork.

Phases of Proposal

For the reasons mentioned above, an upgrade to the dust collection system is being proposed. This is mainly comprised of purchasing a larger, more powerful cyclone, re-working the piping to reduce pressure losses an optimize airflow, and install an automated blast gate system to automatically turn on the dust collection system when tools are being used and to prevent substantial pressure losses from open blast gates. To mitigate excessive noise and fine dust concerns, materials to build a sound-absorbing closet for the DC and three air filtration units are being proposed. Appendix A comprises a CAD drawing of the proposed moves and piping. This will involve several phases.

Moving DC Closet and Some Tools

The current piping layout in the Woodshop results in a long reach of piping between the DC and the table saw, lathe, and sanding areas; thus adding the lathe and sanders to the system would significantly reduce the pressure in the system that is already inadequate. Most light commercial models that PS:1 can fit in the Woodshop cannot provide adequate pressure for the current layout if multiple tools are used at the same time. The new piping layout will reduce the pressure drop at the sanders by 4-5 inches of water, drastically improving dust pickup; Appendix A includes spreadsheets showing the pressure calculations for a hypothetical system where the DC is installed in its current location, and with the proposed layout.

The DC will be located where the plywood rack currently is, and the plywood rack, ShopBot desk, and computer shelves will need to be moved to the left. This will require a three-phase 220V 50A hookup to be installed in the new location.

In addition, to reduce congestion around the 20" bandsaw and drum sander, an additional 220V line will need to be installed where the bandsaw is located on the CAD drawing. This will also reduce wear on those tools' plugs since plugs will not need to be switched out to use the 220V lines.

Construction of Sound-Resistant Cabinet

Before installing the new DC a sound-resistant cabinet will need to be constructed, as the new dust collector proposed is 7-8 decibels louder than the current system. The cabinet will be constructed with double-thick drywall, with two layers of staggered studs insulated with rockwool soundproofing batting; this construction method has an estimated sound transmission class (STC) of 55, resulting in a substantial reduction of ambient noise. See https://en.wikipedia.org/wiki/Sound_transmission_class for more information. Appendix A includes a diagram of the proposed wall construction.

In order to prevent sound coupling and reflecting with the walls and ceiling, the cabinet will not be fastened to the wall and ceiling and will instead have its own back wall and roof, constructed in the same way as the other walls. Return air will be vented through louvered and baffled return grates located on the top of the side walls. The door, which will also be constructed in the same way, will have seals to prevent sound escaping through the door gap.

The cabinet, as well as the DC when installed, will be fastened to the concrete slab floor with concrete anchor bolts.

Purchasing new DC, air filters, ductwork, and blast gates

The cyclone being proposed for purchase is the Grizzly G0638.

http://www.grizzly.com/products/Grizzly-10-HP-3-Phase-Cyclone-Dust-Collector/G0638

This DC can provide ~4000 CFM and 16 inches of static pressure, which is more than PS:1 is likely to require. It should be noted that as systems become 'worn in' and dust is entrained in bends, this pressure capacity will decrease somewhat. An 'oversized' system is better to reduce the maintenance needs. This system also include rope-pulled internal brushes for easily cleaning filter pleats (as opposed to the current method of taking them outside and scraping them clean).

In addition, to remove fine dust, three air filter units are proposed, using this Grizzly model:

http://www.grizzly.com/products/Grizzly-Heavy-Duty-Double-Air-Filter-with-Remote-Control/G9956

The volume of the wood shop is 25' x 75' x 12' = 22,500 cubic feet. Note that for the purpose of air filters the height is 12' though the shop ceiling is closer to 16' - fine dust generated at floor level does not typically reach heights above 12'. To achieve the recommended minimum air exchange of 8 times per hour a flow of 3000 CFM is needed (22,500 cubic feet * 8 volumes/hour * 1 hour/60mins). As discussed earlier about sizing the DC, a factor of safety is needed since maintenance will likely not always occur on schedule, and that the wood shop is not completely isolated from Hot Metals or the loading dock. The filter model proposed has a maximum of 1400 CFM, but since these ratings are for clean air and filters, three units with a 'maximum' of 4200 CFM total will operate under normal conditions slightly above the 3000 CFM goal. Smaller units placed strategically around the shop will move air more effectively than a larger higher-throughpass system.

An inventory of the current ductwork at PS:1 was conducted, and it was determined that the list of ductwork provided in Appendix A is needed.

Ecogate provides an automated system called the 'GreenBox 12' that allows 12 tools to be hooked up to small 24V sensors that will trigger the DC system and blast gate when tools are used. The wires run along the ductwork and do not require any additional electrical work besides that needed at the DC. The system also comes with a netbook that allows the system to track power and tool usage. Ecogate claims their system can reduce power consumption of DC systems by up to 75% by selectively turning on the DC only when needed. Ecogate has agreed to give PS:1 a 10% discount, bringing the quote for the entire system to $8700. Appendix A includes an estimate from Ecogate.

Installation of the system

Should the vote pass, a more detailed work plan will be written to provide a order-of-operations for moving tools, constructing the cabinet, installing the electrical for the new system, installing the ductwork for the new system, wrapping the ducts with sound-absorbing fiberglass and vinyl, and other phases needed in the project. Volunteers will be solicited to help, and minimal disturbance to use of the space will be the goal. It is anticipated that there may need to be a small number of days where the Woodshop is either closed for use or restricted in some way to allow volunteers to safely install the ducting.

Cost Estimate

Grizzly DC: $4900
Grizzly Air Filters: $500 x 3 = $1500
Duct Work (from Oneida Air Systems): $2000
Duct Soundproofing Wrapping: $1200
Ecogate System: $8700
Electrical Work: $1000
Construction materials for sound-proof cabinet: $2000
Total: $21,300
Add 10% for project incidentals: $23,500

Goals

We believe the best course of action is to allocate $23,500 to allow the purchase of a new DC cyclone, air filters, automated blast gate system, and necessary ductwork and incidentals for installation of the ductwork. Undertaking this will improve air quality at PS:1 and general cleanliness in the Hot Metals and Woodshop area.

Vote Language

Authorize the board, or an individual deputized by the board, to spend $23,500 for a new dust collector cyclone, air filters, ductwork, blast gates, and related expenses.
- Authorization to spend these funds will expire 12 months after the vote approval. Money could be allocated in phases if necessary as the project will likely occur in distinct phases.
Authorize the board, or an individual deputized by the board, to draft a basic 'task list' or work plan to lay out tasks for installing the system, and to solicit volunteers for each phase.
Authorize the board, or an individual deputized by the board, along with the volunteer group, to tape off work areas as needed in order to perform necessary work safely.

Voting

Quorum:106

Present:108

For:96

Against:8

Abstain:4

Receipts

Appendix A

All the files references above can be found at this Google Drive link:

https://drive.google.com/drive/folders/18Sm54CsFdrE5_XgESwcmJWEmdbKc_Gn5?usp=sharing