Best Practices for Blast Room Maintenance

Q: My company just invested in new blast room facilities. What advice do you have for regular maintenance?

A: A high-quality blast room is a large capital expense. Failure to give it basic care will severely shorten the life of this major investment. The company from which you purchased your blast room will most likely provide you with a full maintenance schedule broken into what needs to be done each day, week, month, and year. And while those instructions should serve as your guide for blast room care, here are seven items that should go right to the top of the list.

1. Filters: replace, don’t clean

Cartridge dust collector filters are self-cleaning; therefore, you should not send them out to be cleaned. Dust collectors are designed to blow air on filters, which knocks off caked-on dust from the filters while in operation.

Of course, at some point, the filters get sufficiently clogged that they no longer function properly. Plenty of companies will clean them, but the process degrades and weakens the filter material — just like clothes in a washing machine. At this point, you should get new filters, not clean the dirty ones. New filters are relatively inexpensive and will obviously be in better condition than ones that have been subject to the wear and tear of the cleaning process.

Because the filter material has been degraded, the vacuum from the reclaim system may punch a hole in it, causing the collector to suck dust straight into the mechanism. So while you may save a few dollars cleaning your filters, you’ll pay on the other end when you need to buy a new blower.

2. Don’t skimp on filter quality

Blast room owners often will shop around for the lowest price on filters but, as the saying goes, you get what you pay for. Not only are the cheaper filters made of a lower-quality material that wears quickly, they will generally have a lower MERV Rating (Minimum Efficiency Reporting Values).

MERV ratings signify an air filter’s effectiveness at reducing airborne particles and contaminants. The higher the ratings, the more effective a filter is at capturing smaller airborne particulates. So a filter with a lower rating will allow small-micron items to pass through undeterred.

3. Protect your blasting equipment

You’ve seen what abrasive blasting can do to the parts you process. Now, consider: That same media is running through your blasting equipment —what do you think it’s doing? Everywhere your media travels, every piece of material that it touches in your blasting operation is subject to the same abrasive effects as the items you’re blasting. The hose and the nozzle are especially susceptible to this wear and tear, but there really is no part of the equipment that doesn’t feel the wrath.

Because the dust from the abrasive media is traveling through the ductwork at an incredibly high velocity, it should be thicker than regular HVAC ductwork. (We recommend lining the ductwork with rubber to minimize erosion.)

4. Practice good housekeeping

Blast rooms are often viewed as filthy beasts that ultimately spread dirt and dust throughout a facility. They are dirty, but usually just on the inside. The real mess is caused by people who don’t practice good housekeeping.

• Often, workers will open the doors to the blast room while the dust is still floating around. A good rule of thumb is to wait 30 seconds to a minute after blasting to allow the dust to settle before opening the doors.
• Sometimes, forklifts are required to move parts or blasting media into the room. The forklift ends up accumulating grease on its tires, driving back into the shop, then repeating the process.
• Blast workers sometimes drag the hose out of the room, bringing the media with them.
•  Depending on the blast room configuration, workers might be loading media into a hopper that’s situated outside the room. It’s inevitable that some of that media can end up scattered on the facility floor.

Here are two pieces of simple advice that can go a long way toward keeping the area surrounding the blast room spotless (almost): 1: Ask those workers doing the blasting to be aware of these muck-producing activities and minimize their occurrence through constant vigilance. 2: Be sure workers keep a broom handy so they can sweep any stray media or particulate back into the room when they open the door.

5. Avoid the grind

The augers used in vacuum reclaim systems sit in a kind of trough but don’t actually touch bottom; rather, there’s a hanger bearing that keeps the auger suspended an inch or two in the air. As the media is pushed into the trough, it doesn’t come out until the space between the bottom of the trough and the bottom of the auger is filled. It’s designed this way so that when the auger begins to run, it’s basically working in a bed of media, not sitting flat on the bottom; if it were, the auger would grind right through the trough.

However, if the hanger bearing wears thin and that auger drops down, it will grind into the trough and eat right through the metal at the bottom. Now you’ve gone right through your floor, and all your media will start leaking out. This doesn’t take place overnight; however, if the hanger bearing isn’t checked regularly, it will happen before you know it.  

6. Beware of system overload

Speaking of the vacuum reclaim system, be careful not to dump too much spent media into the trough. These systems are equipped to regulate how much media falls through the trough down to the auger because it’s got to suck it into the cycle, spin it, then suck out the dust and debris. That can only happen at a certain speed.

Unfortunately, workers will sometimes drop a day’s worth of media on top of that auger all at once, after which they try turning it on. Now it won’t work because it’s blocked off; the auger has an incredible amount of steel grit sitting on it, and when you try starting it up with that volume of material, the spring is inevitably going to break at the weakest point.

Besides not overloading the reclaim system, don’t shut the system off while it still has media inside. A few types of blast rooms have their control panels set so they can only perform certain functions after others have been completed, thus avoiding the problem of starting them prematurely.

7. Conduct visual inspections

Make sure there’s no cracked glass in the windows. Also, when checking the windows, examine the seals around the frame, both inside and out, to ensure there are no gaps or crevices. Blast rooms are kept under negative pressure. So if you were to punch a hole in the room, it’s not going to blow material out of the room; it’s going to suck it into that hole, contaminating the blasting process.

Ensure that the glass shields on all the lights are in good shape. (Every now and then you should clean the light lenses so that the room is adequately illuminated.)

Inspect your Personal Protective Equipment (PPE) regularly to ensure everything is working properly: helmets, CO monitors, air supply, etc. It’s a good idea to train your blast room operators to check the equipment themselves since they’re the ones using it. Create a checklist to make inspection simpler and quicker.