Preconditions
Tools / Equipment
The following equipment will be required:
- Hard hat
- Safety glasses
- Steel toe boots/shoes
- Gloves
- Ear Plugs
- Face Shield
- Rain Suit (optional)
- Rubber boots/ overshoes (optional)
- Goggles (optional)
The following tools will be required:
- Pressure Washer
Requirements
Requirements for this guideline include:
- Qualified Mandros Painting personnel.
- Job Safety Analysis (JSA).
- Notification of all parties involved.
Hazards
The following hazards may be present:
- High Pressure Water
- High Temperatures
- Flying Debris
- Electrical Hazards
- Slips, Trips, and Falls
References
Manufacturer’s manuals and related documents
Refer to the following materials for detailed information about this task:
- Original Equipment Manufacturer’s (OEM) Service Manual – Landa
- Operating Manual
- MPI Safety Manual
Types of Soils and Solvents
Guideline for Types of Cleaners
General Debris
Dirt, debris, mud, chalking paint, or any other
surface contaminants that do not require chemical solvents
to dissolve can be cleaned with water or steam.
Oily Soils
Hydraulic, lubricating, and light oil and oil based
rust preventers are some examples. When present as thin
films or small residues, and when very viscous in nature,
these soils may be removed with alkaline cleaners. On more
stubborn areas, solvent cleaners may be needed because
the longer a soil ages the more difficult it is to remove.
Semisolid Soils
Viscous oils, greases, and heavy rust preventers
are some examples. These soils are often removed with
heavy duty alkaline cleaners or a combination of a solvent
followed by an alkaline cleaner.
Soluble Salts
Soluble salts, like chlorides, sulfates and nitrates
are found on surfaces everywhere – in marine environments
or as residue left by chemical compounds, like de-icing salts
or industrial emissions. Soluble salts pull moisture from the
air, causing protective coatings to fail. They can also cause
degradation of the substrate, including ferrous and nonferrous metals, concrete, foam, plastics and others. Left
unchecked, the salt contamination corrodes into deep
pockets in the substrate, making decontamination more
important and challenging. Protective coating failures are
costly due to repair and lost productivity, and can be
hazardous.
Soils Containing Solids
Some examples are mud, carbonized oils, tape
adhesive, and corrosion products. These soils are usually
the most difficult to remove and may require a combination
of solvent, alkaline pressure spray, and scrubbing, and, in
the case of corrosion products, acid pickling to complete the
cleaning process.
Aged or impacted soils are generally the most
difficult to remove. It is necessary to remove not only the soil
but also any cleaner residues, which may subsequently
contribute to further corrosion or adversely affect coating
performance.
Guideline for Types of Cleaners
Solvents
Aliphatic petroleum solvents (kerosene, VM & P
naphtha, mineral spirits), aromatic solvents (toluene, xylene),
ketones (Acetone, MEK, MIBK), chlorinated solvents, or a
combination of these, are used to dissolve and remove oily
soil. Petroleum solvents may be used in hand, soak, or spray
cleaning and are efficient in removing oils and greases.
Chlorinated solvents are generally used in vapor degreasing
units but may also be used at ambient temperatures by
immersion or spray. They are effective in removing heavy
oils, greases, and waxes. Chlorinated solvents should be
should be inhibited against hydrolysis to prevent hydrochloric
acid from forming in the presence of water. Acidity may etch
the metal. Solvent cleaners offer the advantage of leaving
the surface dry after cleaning and eliminating the need for
additional rinsing.
Environmental and health regulations restricting
the use of organic solvents have become very stringent in
recent years. Thus, with the exception of solvents used to
clean small areas, water based alkaline or acidic cleaners
are more common today.
Alkali
Alkaline cleaners, such as TSP, are usually
composed of highly alkaline salts, such as sodium
hydroxide, silicates, and carbonates along with surfactants,
sequestering agents, inhibitors, wetting agents, and/ or
soaps. They function by wetting, emulsifying, dispersing, and
solubilizing the soils. These are generally more efficient at
elevated temperatures.
Detergents
Detergent cleaners, such as Simple Green, are
composed of buffering salts, sequestering agents,
dispersants, inhibitors, and wetting agents and/or soaps.
They function by wetting, emulsifying, dispersing, and
solubilizing the soil, generally becoming more efficient when
used at temperatures ranging from 150 degrees F (66
degrees C) to boiling.
Acids
Acid cleaners, such as Clean-n-etch, are usually
composed of fairly strong acids with small quantities of
surfactants, water miscible solvents, and organic wetting and
emulsifying agents. Acid cleaners remove a soil by chemical
attack, dissolving the reaction products. They are used
primarily to remove corrosion products that cannot otherwise
be efficiently removed by mechanical cleaning methods.