Tag: waterjet

Comparison of WaterJet and Abrasive Blast Coatings Removal

Here is a posting of a comparison video of UHP WJ coatings removal (hydroblast, waterjetting) with dry abrasive blast cleaning. (AB) It is the smallest particles which drift from the site, that you never see, which causes lung damage. One of the abrasive blast sites was in an 1850’s california village. few precautions were taken for the workers, much less the public. What the observer should know is I found three examples of public exposure to abrasive blasting; the Ultra-high-pressure waterjetting was made to show the close-up view of the mist steaming from the surface. There was none to little flash rust.

 

Microscopic Analysis of Steel after Waterjet Cleaning

In the late 1990’s,  I received a report from Materials Evaluation Laboratory.  The report is copyrighted.  The pump company had cleaned UHP WJ on panels supplied by a major oil company.  Materials Evaluation Laboratory analyzed the substrate with microscopy and metallurgy compared to abrasive blasting.  This was at the time that UHP WJ was scarce and people were wondering what was happening at the surface. Would the surface be stressed?

Their conclusions:

1.  Pressurized water effectively removed rust and other corrosion products from metal surfaces. This was done
with minimal disturbance of microstructural features.
2. Methods using abrasive particles were necessary for the removal of adherent mill scale. Those techniques cause
severe distortion of the metal surface.
3. The pressurized water method was considered the best preparatory cleaning for non-destructive inspection.
It offered a more “authentic” representation of the surface than the other methods evaluated.

This material is copyrighted.  Please acknowledge the source. The Advisory Council can use it for educational purposes.  It is not considered an endorsement nor recommendation.

Materials Evaluation Lab effect on surface 1991

Materials Evaluation Lab effect on surface 1991 Page 1 sanatized

Common Safety Errors Found in Pressure Washing, Hydroblasting, or WaterJetting

Common Safety Errors Found in Pressure Washing, Hydroblasting, or WaterJetting

Reviewed: 2011-05-17 by Lydia Frenzel

The Advisory Council compiled a Special Report of errors, accidents, incorrect assembly practices and faulty work habits in 2002. Luis Ortega Trotter, who is now deceased, from AcquaBlast in Brazil provided the photos to the Advisory Council WaterJet Workshop on Surface Preparation held at the 2001 WJTA Conference. Ortega was concerned about the difference in the training and education of the work force in Central and South America and developing countries, compared to those of North America-Canada-USA-Europe.

These mistakes seem like “It couldn’t happen on my site.” They are mistakes that might not be observed in a quick inspection. Yet Lydia Frenzel gets calls about cut or frayed hoses, kinked lines, and pressure relief valves that are installed incorrectly. Don’t let this happen on your site. Contact the Advisory Council for a copy.

Luis Ortega received the WJTA Best paper award in 2001 for his Comparison of Abrasive Blasting, Wet Abrasive Blasting, Waterjetting-Hydro Blasting, Needle Gun cleaning, and Grinding on a Pulp Mill in Brasil (Brazil). The paper compares salt residuals and costs. Contact the Advisory Council for a copy and his presentation. Frenzel lost contact with AcquaBlast after Luis Ortega died and Juan C. Ortega became the owner. Web site is www.acquablast.com.br; email: acquablast@acquablast.com.br

The errors include:

1 Incorrect installation of water filter in the wrong direction resulting in deformation of the pressure filter

2 Blown-out hose out due to incorrect installation of particulate water filter.

3 Pressure relief seal installed incorrectly

4 Over tightening of fittings.

5 Caustic in by-pass valve resulting in failure

6 Missing pipe connection that results in blow-out of concrete

7 By-pass assembly damaged from being dropped or falling

8 Cutting of hoses on sharp edges

9 No hose covering or sheathing or protector

10 Destruction of triggers of jetter pistol/gun from caustic so that dual trigger protection was not operational

11 Incorrect scaffolding

12 Employee without gloves, security-safety-tie-off belt; single trigger instead of dual trigger, gun

13 Employee placing a hand in the water bypass (water dump hose)

14 PVC gloves instead of steel mesh or waterjet safety gloves

15 No eye protection or gloves

16 No whip lock or whip check

17 Terminal end of high pressure connection has damaged thread, no lubrication