Alternative Technologies and Avoiding Entry
Robotics and high power vacuum systems are just two of many options for cleaning, repair, or inspection that might require an entry.
I have never actually entered a confined space, and to be honest, I have never really wanted to. I have, however, been responsible for ensuring the safe and effective entry into literally hundreds of confined spaces. One thing is for certain: The safest entry is no entry at all!
The purpose of this article is to review the various reasons that one may have for entering confined spaces, and then to offer a variety of alternative technologies and approaches for avoiding entry in the future. While it is unlikely all organizations can eliminate the need for confined space entry, it is very likely many organizations can at least reduce the frequency of entry.
Definitions
Let's begin by reviewing the definition of a confined space. A confined space is "A space that is large enough and configured in such a way that an employee can enter and perform assigned work. It also has limited or restricted means of entry or exit (e.g., tanks, vessels, silos, storage bins, hoppers, vaults, and pits are spaces), and is not designed for continuous employee occupancy."
The implication of the definition is that entrants into a confined space where hazards are present have greater risk because of the work conditions. With that as a basis for our discussion, let's proceed.
Reasons for Entry
There are many reasons why confined space entry may be required (at least at first glance). Some of these might include:
- Product removal: A site may have to remove a product from a tank, silo, vault, or similar space for reprocessing, or there may be a need to change out production to a different product.
- Spills: Spills or releases may flow to vaults, sewers, catch basins, pits, or similar locations.
- Maintenance: Confined spaces of all types may require entry in order to perform repairs, complete inspections (regulatory, post-incident, and or good engineering practices), provide for new installations, etc.
- Cleaning: Cleaning may be required for decommissioning of equipment, as a follow-up to product removal or spills, or in preparation for maintenance activities.
Why Not to Enter
Despite the many reasons why confined space entry may be required, there are overriding reasons why not to enter. Consider, for example:
- Chemical exposure: Many entries are into spaces containing, or formerly containing, hazardous chemicals. Obviously, work in an area with reduced natural ventilation increases the potential for exposure through inhalation, and because of the nature of the space, physical contact may be more likely, as well.
- Physical hazards: Entry into confined spaces can subject the entrants to entrapment, engulfment, mechanical hazards, heat, cold, and a host of other hazards.
- Equipment requirements: Entries require the use of specialized equipment, including extraction devices and other rescue equipment. Much of this specialized equipment is of no use for other workplace activities.
- Personnel requirements: A safely performed entry will require at least three people, and possibly more. Other personnel, including those assigned to rescue services, will necessarily be on standby. The overall commitment of employee resources for these activities can be quite significant.
What Are My Alternatives?
So, you ask, if I have tasks to perform, and yet I have all of these risks and reasons not to enter, what are my alternatives? Let's consider several specialized pieces of equipment, as well as common and not so common techniques.
Product/Material Handling Equipment: High Power Vacuum Systems
In order to remove material from a confined space without entry, one option might be a high power vacuum system (see Figure 1). These systems can be truck- or trailer-mounted, can achieve air flows of 500 to 7,000 cfm, and are capable of establishing 15 to 30 inches of Hg vacuum. The units can be equipped with suction lines of up to 8 inches in diameter, allowing for removal of even large debris, and will move material up to 1,000 feet laterally. They can be operated in wet or dry mode and may be further equipped with HEPA filtration. Other special options include explosion vents, special interior coatings, internal wash down systems, swing out cyclone collection, and specially designed drop-out collection containers. With a high power vacuum system you can move abrasives, brick, catalysts, cement, chemicals, oil, sludge/slurries, clay, coke, and virtually any other debris from virtually any confined space.
Specialized Cleaning Equipment
There are several options available for cleaning without entry. These can include water jet cleaning, abrasive blasting, and chemical cleaning.
This article originally appeared in the February 2004 issue of Occupational Health & Safety.