| Overview: |
A portable vacuum sanding system will
effectively capture sanding residue and be mobile/light enough to be operated by one
person. The unit can be used to sand composite structures such as radomes. The system
integrates a vacuum cleaner with vacuum assist sanders for eliminating airborne toxins
(including lead, chromium, and dust) while removing paint from both metallic and
nonmetallic aircraft structures. The system incorporates three-stage filtration composed
of a filter bag, prefilter, and HEPA filter. The
effect this technology has on pollution prevention is that the portable vacuum sander
removes coatings and corrosion from composite or metal structures while capturing the
solid waste. Vacuum sanding eliminates airborne particulate matter and potential lead dust
exposure hazard. When compared to chemical paint stripping, this technology eliminates the
generation of waste solvent.
OSHA 1910.1025 requires that sanding and grinding
operations take place without exceeding the lead permissible exposure limit (PEL) of 50
g/m3. The vacuum sander helps meet this requirement. OSHA Standard 1910.1025
states: "Where vacuuming methods are selected, the vacuums shall be used and emptied
in a manner which minimizes the reentry of lead dust into the workplace." Therefore
workers should exercise care when using and emptying vacuum units.
An example of one system is the Clayton cleaner/sanding
system Model 660-DM-1000. This system incorporates one vacuum cleaner, two vacuum assist
sanders, two vacuum assist grinders one package of 6 mil polyliners, one Y adapter, one
package of filter bags, two packages of prefilters, and one tool caddy. All accessories
are compatible with each other.In 1994, the Navy procured approximately 124 units for use
on both shore-based and shipboard activities. In addition, several Air Force bases use the
units. Currently, several vacuum sanding units are being used on composite radomes at
Naval Station Mayport in Florida, but evaluation of the system is not complete.
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| Compliance Benefit: |
The portable vacuum sanding system
eliminates the generation of waste solvent when compared to chemical stripping.
This benefit helps facilities meet the requirements of waste reduction under
RCRA, 40 CFR 262, Appendix, and may also help facilities reduce their
generator status and lessen the amount of regulations (i.e., recordkeeping,
reporting, inspections, transportation, accumulation time, emergency prevention
and preparedness, emergency response) they are required to comply with under
RCRA, 40 CFR 262. In addition, less hazardous materials (i.e., solvent)
are required to be purchased and stored on site and therefore, the possibility
that the facility would meet any of the reporting thresholds of SARA Title
III (40 CFR 300, 355, 370, and 372; and EO 12856) is decreased. It
should be noted that the portable vacuum sanding system generates slightly
more hazardous waste when compared to traditional hand sanding but this
factor may be counterbalanced by employee exposure benefits.
The compliance benefits listed here are only meant to be used as a general
guideline and are not meant to be strictly interpreted. Actual compliance benefits will
vary depending on the factors involved, e.g. the amount of workload involved.
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| Materials Compatibility: |
The system can be used in most
applications where chemical stripping, hand sanding, and mechanical sanding
methods are used. No materials compatibility issues were identified.
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| Safety and Health: |
Airborne dust, which is a major
safety and health concern with any sanding operations, is essentially eliminated
using the vacuum sanding system. However, eye protection and hearing protection
are recommended. The system is designed to be in compliance with OSHA Standard
1910.1025 for use during sanding and grinding operations. Consult your local
industrial health specialist, your local health and safety personnel, and
the appropriate MSDS prior to implementing this technology.
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| Benefits: |
- Reduces airborne pollution from current power sanding
operations.
- Improves efficiency of operations.
- Improves personnel safety by collecting and containing paint
dust particles.
- Provides a cost-effective means to remove paint from
composite structures that cannot be removed from a ship.
- Reduces labor hours for manual sanding operations.
- Portable unit.
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| Disadvantages: |
- Capital equipment investment is required.
- Operator training is necessary.
- Operator time, maintenance requirements, handling, and
disposal of waste varies with the material to be stripped.
- Quality of stripping is dependent on skill and experience
level of the operator. Composite substrate can be damaged.
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| Economic Analysis: |
Processing radomes and equivalent
composite structures using the vacuum sanding system has shown some decrease
in process time for a radome assembly. However the largest benefit is personnel
safety. The vacuum and filtration process eliminate airborne toxins (including
lead, chromium, and dust) generated when preparing coated surfaces for refinishing.
The vacuum sanding system interfaces well with site operations, minimizes
site clean-up, and provides a safer, healthier work environment.
Assumptions:
- Labor for sanding and grinding is the same for either
system.
- Number of sanding disks or wheels is the same for either
system.
- Filter bags are changed once per month taking 5 minutes.
- Prefilters are changed once per year taking 5 minutes.
- HEPA filters are changed once every ten years taking 5
minutes.
- Filter bags cost $9; prefilters cost $18; HEPA filters cost
$369.
- Labor rate = $40/hr.
- Setup/Cleanup for conventional sanding/grinding operation
takes 80 hrs/yr.
- Setup/Cleanup for vacuum sanding takes 40 hrs/yr.
- Waste disposal quantities are slightly higher for vacuum
sanding because of the disposal of filters.
- Waste disposal costs $1,200/ton or $0.60/lb.
- 500 lbs. of waste material from sanding operations are
generated/year.
- 25 lbs. of filters are generated/year.
Annual Operating Cost Comparison for
Portable Vacuum Sanding and Conventional Sanding
| |
Conventional Sanding |
Portable Vacuum Sanding |
| Equipment Cost: |
$0 |
$4,955 |
| Operational Costs: |
|
|
| Setup/Cleanup Labor: |
$3,200 |
$1,600 |
Maintenance Labor
(changing filters): |
$0 |
$43 |
| Filter purchases: |
$0 |
$163 |
| Disposal: |
$300 |
$315 |
| Total Operational Costs: |
$3,500 |
$2,121 |
Economic Summary
Annual Savings for Vacuum Sanding: $1,379
Capital Cost for Equipment/Process: $4,955
Payback Period for Investment in Equipment/Process: 3.6 years
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| Approving Authority: |
Approval is controlled locally
and should be implemented only after engineering approval has been granted.
Major claimant approval is not required.
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