Why Abrasive Blast Coating Removal with Spent Abrasive Recycling is most often a better choice than High Pressure Water Jet.
SAND BLASTING GROUP STUDY BY THE ENVIRONMENTALLY SAFE SOLUTIONS CONSORTIUM
First Presented: 4/13/07 San Francisco, CA
For a number of years there has been an effort to promote high pressure water jet cleaning as a replacement or alternative to Abrasive Blasting. We believe that ultra high pressure water jet wash systems have a place in the care and maintainace of coated structures but do not in any way offer a consistent replacement alternative for abrasive blasting.
This paper will outline the environmentally safe use of
Abrasive Blasting for coating removal and surface preparation.
Abrasive Blasting when properly employed is the safest, most cost effective method to remove coatings and prep for new coatings on most substrates.
The tried and true is from most peoples experience the best method to win the bid and actually profit in a competitive environment.
Despite the buzz about ultra high pressure water jet cleaning in most cases traditional sand blast methods with proper engineering controls will create a superior anchor pattern / profile in less time and overall costs than ultra high pressure water jet cleaning. When you add in a legitimate spent abrasive recycling program like those offered by several companies in the United States, one can complete with a cost effective cradle to grave loop from the selection of proper abrasive to recycling of the waste generated from abrasive blasting.
The goal is always a happy client owner and a long lasting coating.
Abrasive blasting with spent abrasive recycling can achieve this
time and again while it also eliminates land fill waste and
associated potential owner/generator liability.
B. Discussion
One San Francisco bay area company offered has offered
Abrasive Blast Media and Spent Grit Recycling for over ten years.
Annually this program has been used in over three hundred
locations by Commercial and Industrial Abrasive Blasting contractors
These Contractors used Abrasive Blasting to remove coatings from
an estimated total over seven million square feet of surfaces
on Navy ships, commercial fuel and water tanks and other structures.
They then enlisted the assistance of Kleen Industrial Services
To address the resulting 40 million pounds of spent abrasive blast
Media and the entrained removed coating.
K.I.S processed the spent Blast media by:
1/ Taking a pull sample from the spent media pile
2/ Characterization of the waste with proper testing with Cam 7 or
TCLP.
3/ Transporting and storing the spent abrasive.
4/ Remove any non abrasive material like gloves, tapes, and wood
pieces and other debris from the spent abrasive.
This may include in many cases screening the spent abrasive.
5/ The spent abrasive is then transported to a proper facility
That completes a beneficial reuse of the media, eliminating
Disposal of the spent abrasive in landfill.
For example spent abrasive blast media becomes “clinker” for a
concrete kiln or if non-hazardous it may be used a mix aggregate
for road base or asphalt pavement.
One company, Kleen Industrial Services(See www.kleenblast.com for data)
Has full California DTS approved programs to recycle spent abrasive
and provides an actual Certificate of Recycling upon completion of a
project.**
In comparison high pressure water jetting will re-filter the water used
And may concentrate the waste into a form that often needs to be put in
A toxic waste disposal facility.
“An abrasive blast and recycle program is responsible environmental
stewardship that may also eliminate the owner / generators
cradle to grave liability for waste.”
These two points alone make an excellent case to use this or similar abrasive blast and recycle programs.
Other issues that present with ultra high pressure water jet cleaning:
- Flash rust is an issue. The contractor has to be aware of the fact the owner of the facility or ship requires a clean surface and most often
Will not accept a rusted surface.
- Fact is -flash rust is not acceptable in most cases for a number of reasons.
3 . Hydrogen embritlement – is it real? It was real enough for the
USAF To stop using high pressure cleaning of tail sections of C 5 A
and other aircraft a Warne Robbins AF base over 7 years ago.
The energy released in UHP Wash may hide imperfections in steel
Structures, and in theory may weaken steel as an affect of
realignment.
4. Abrasive Blasting Creates a uniform surface profile- high pressure
wash cleaning does not create a uniform surface profile.
- There are always questions on how ell the high pressure water will remove deep contamination and chlorides. Water recycling systems may make this issue more prominent. Cross contamination is the bane of any effort filter/ clean and reuse and element of a cleaning / removal process.
C. Conclusion: the top 10 Reason to Use Abrasive Blasting with Spent
- Customer acceptance is high. As Bobby Sanders of Delta Sandblasting* says, “It’s what you do to get it done right the first time. Sandblast because you know the results.”
- Realistic replication of the process is a reality not a goal. With modern SSPC & NACE Operator Training and Certification. This is essential along a premium quality Abrasive Like Kleen Blast, WGI Emerald Creek or GMA Garnet . Take the correct operator and abrasive and combine it with quality Equipment Like Clemco , Schmidt or Empire that allow Flow, Pressure, and process controls and Sandblasting is a replicable, repeatable process.
- Consistent substitute profile and cleanliness is the result of the controlled sandblast process.
- No issue of contaminants remaining in substitute no or low chlorides in the abrasive most often yields no chlorides left on the blasted substrate.
- Initial investment is 1/10 – 1/100 of that of high pressure water jet cleaning wash.
- No Clean Water Act issues with discharge, use and reuse of and proper disposal of concentrated liquid wastes and blinded filter.
- Most abrasive medium suppliers also sell abrasive equipment and the best offer Spent Blast Abrasive Media Recycle or Disposal programs.
- Abrasive Blasting with properly trained workers keeps workmen compensation claims down which preserves a contactors bonding ability and keeps the contractor access to bid in compensation ratecontrolled facilities like oil refineries.
- One Should Look OSHA Reports on the many dangerous accidents occur in Ultra High Pressure Water Jet Cleaning. Check this and check with your insurance carrier before you consider a UHP system.
- Slug, Garnett, Sandblast and Aluminum Oxide Salesmen are nicer people then High Pressure Water Cleaning guys. Well maybe not the Garnet guys.
Recycle Programs like that of Kleen Blast & Kleen Industrial Services
- Maximize profits. Total Cost and Risk per Sq. Foot is minimized.
- Liability “Cradle to Grave Recycle Programs eliminates potential liability of disposal of spent abrasives or concentrated high pressure wash residue in landfills.
- Premium quality blast abrasives, equipment and skilled operators will always perform on time and on budget.
* Delta Sandblasting a Premier Abrasive Blasting contactor that
Specializes in tank work on Commercial and Navy Ships:
Contact Bobby at 707-
** The Kleen Industrial Services Program is now so much in demand they
Are also recycling waste from industrial users like powder coating
Companies which used dispose of their spent abrasives in landfill.
LOOK FOR MORE PAPERS next month on this from:
SAND BLASTING GROUP STUDY BY THE ENVIRONMENTALLY SAFE SOLUTIONS CONSORTIUM |
