Early adopters made the switch to vapor blasting to leverage the low-pressure, low dust feature of the process to ensure compliance with heightened OSHA respiratory regulations and mitigate physical hazards. Over time, users began to relate the major advantage of vapor blast equipment is the ability to degrease, blast clean, aqueous clean, and rust inhibit in one system with no need for complementary process equipment, as well as the frugality of the system in terms of consumables like grit, water and energy. After making the switch, however, contractors are happy to discover a "hidden" benefit: real cost savings due to reduced containment.
OUT OF CONTROL COSTS
Both wet jetting and dry blasting propel debris at a high velocity and disperse widely, which is why these processes often require hermetically sealed areas (with associated negative air pressure, filtered exhaust, and sealable entryways) to prevent toxic debris from poisoning aquatic life or leaching into soil to bioaccumulate up the food chain after being absorbed by plants. Containment measures can be complicated, increase setup time, mandate ventilation and exhaust filtration systems, and require the use of large containment trucks and equipment. This is especially true for surface preparation of bridges or structures over or near water require fully-engineered structures, where 40% of a dry blast operation budget and considerable time can be eaten up by containment measures and the labor needed to erect and dissemble them.
Low volume consumption of water and grit media inherent in the vapor blasting process means a low volume of waste product will need to be contained, so large containment trucks and equipment aren't needed. Containment is much simpler. Even in high-traffice areas, partial containment, in the form of a tarps supported by a frame structure and/or plywood barricade is sufficient. In most cases of vapor abrasive blasting (other than abatement jobs), ventilation and exhaust fitration are not required.
Because particle emissions and debris are encapsulated and weighed down by water vapor in the vapor blasting process, it can be contained using less extensive measures. Ground containment often consist of simple, inexpensive anchored tarps overlapping and overlaid with a geotextile material that allows water to pass through while filtering abrasive and debris. At the end of the job, one simply wraps up the geo-textile fabric and deposits it in a drum or container. For large surface preparation jobs like tanks and heavy machinery, constructing a berm lined with geotextile fabric may be prudent to contain small amounts of hazardous runoff.