Removing Graffiti from Historic Masonry (Part D)
Health and Safety Considerations
Most of the chemicals used for graffiti removal are dangerous to workers,as well as to others who may be in the vicinity. Organic solvents are toxicby ingestion, inhalation, and skin contact. Material Safety Data Sheets(MSDS), available from the product manufacturer for all paint-removal products,should always be consulted and followed. Identification of hazardous componentsand checking with chemical reference works will help assure that the leasthazardous, but most effective, products are selected.
Generally speaking, it is a sensible policy to carry out all graffitiremoval in well-ventilated conditions. Some solvents can be used only outdoors,and sometimes forced ventilation may be necessary even there, requiringworkers to use air-fed respiratory equipment to avoid wind-blown fumes.Smoking, eating or drinking must not be allowed when cleaning is in progress.
Some materials used for graffiti removal are so corrosive that accidentalcontact can cause serious, permanent scarring and painful injuries. Wearingappropriate protective clothing must be strictly enforced. Mandatory personalprotective equipment (PPE) normally includes face shields or safety glasses;long, chemical-resistant gloves; face masks with respirators for organicsolvents; and possibly, full protective clothing with an independent airsupply.
All smoking and open flames should be rigorously excluded from workareas; many solvents are flammable or highly explosive in vapor or liquidform when mixed with air. Solvent residue, used swabs, cloths, overallsand all other solvent-contaminated items should be safely and legally disposedof, or properly stored-even overnight-away from potential sources of fire.Electrical equipment may require explosion-proof fittings when used withcertain solvents.
When electric pumps and pressure-spraying equipment are used, it isespecially important that all necessary precautions be taken to avoid electricshock. Water sprays and puddles on the ground present a potentially dangeroussituation, if they come into contact with temporary wiring at worksiteswhere graffiti is being removed. Such hazards must be carefully monitoredand controlled.
As with any construction project, attention should always be directedtoward the general safety of the workers and passers-by, but also towardpossible damage to the resource itself that might result from carelessplacement of ladders, or scaffolding. Chemicals used for masonry cleaningcan also damage adjacent metals, glass, and painted surfaces, as well asvegetation. Product manufacturers' instructions should alwaysbe closely followed to avoid such inadvertent "collateral" damage.
