Air cascade systems may consist of either ISO/UN/DOT cylinders or ASME vessels. They may be used as a cascade refilling system or bulk refilling system. They can be arranged vertically or horizontally too. ASME storage vessels never have to be hydrostatically retested, where DOT, ISO and UN cylinders do require scheduled retesting of the cylinder to insure it is safe to use.
ISO-UN-DOT air cascade cylinders are the most prolific cylinders used to refill your self-contained breathing apparatus (SCBA) with either cascade or bulk filling methods. The picture above depicts a typical air cascade system with UN/ISO/DOT cylinders, with CGA nuts/nipples, pipe tees, flexible 6000 PSI pigtails, pressure adjustable regulator, fill hose assembly and a wall mounting bracket for the cylinders. ISO cylinders are available in 2400, 4500, 5000 & 6000 PSI. (165, 310, 345, 414 BAR
Please
note that the systems below are examples and there is no limit to how
many storage bottles you can have on your cascade system.
We
have also included a chart below to give you an example of how many
fills you can obtain from your storage system before you need to rely on
your compressor to top up your SCBA. As you can see storage is critical
during an emergency on how may SCBA bottles you will be able to fill.
We have eliminated the part of the chart which shows bulk fills as this
is not an efficient way to use your air storage.
Fills from Storage
Instructions:
- Select the type of BA cylinder to be filled from top of the chart.
- Find the fill method and desired number of storage vessels in the left column.
- Select the starting pressure of DOT storage, either 5,000 or 6,000 psi.
- Intersect the cylinder type with the number of storage vessels to determine number of cylinder fills and RF. Residual Factor (RF) represents
residual storage volume which may be utilized in conjunction with a
compressor to fill BA cylinders when storage pressure alone is
insufficient to fill the cylinders to capacity. By adding compressor
cylinders filled per hour, cylinders filled from storage, and RF the
maximum number of cylinders filled from a complete air system may be
determined.
| | 2216 PSI (45CF) 30 min. | 4500 PSI (88CF) 30 min. | 4500 PSI (88CF) 1 hr. |
Fill Method/Vessel | Start PSI | Fills | RF | Fills | RF | Fills | RF |
---|
Cascade 2 | 5000 | 15 | 4 | 5 | 13 | 2 | 8 |
6000 | 18 | 4 | 8 | 12 | 4 | 6 |
Cascade 3 | 5000 | 25 | 4 | 9 | 17 | 4 | 10 |
6000 | 30 | 4 | 15 | 13 | 7 | 7 |
Cascade 4 | 5000 | 35 | 4 | 15 | 19 | 7 | 10 |
6000 | 42 | 4 | 2 | 15 | 10 | 8 |