Omicron Specifications

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There are three essential values required to select an automatic screen filtration system:

• Maximum flow rate (GPM)
• Filtration degree
• Incoming pressure

1. Determine the maximum flow rate

If water is sent to a roof tank, it is simpler to determine a max flow rate since it is limited by the capacity of the house pumps, and how many will operate at the same time. The max flow rate of a constant pressure system can be more variable as it depends on real-time demand. However the max flow rate value is determined, it must be established in order to size filtration correctly.

2. Select a micron rating

For practical purposes, in most domestic water filtration applications there are two choices: 10 or 25 micron. An intermediate degree, 18 micron, is also available. When selecting, it is better to think of a filtration degree not as an absolute but as percentage reduction of overall Total Suspended Solids (TSS) or Turbidity (NTU). Finer filtration (a smaller micron degree) reduces more TSS / NTU. It is not as if all particles larger than the specified micron size will be stopped, and all particles smaller will pass through. Filtration coarser than 25 micron is of limited value for particle filtration in a domestic water application, since very few particles in municipal water are as large as 25 micron.

In the actual application, the difference between 25 micron and 10 with respect to impact on actual water clarity is significant. It is hard to detect an impact on visual water clarity after 25 micron, whereas the impact is likely to be observable after 10 micron. That is why we recommend 10 micron unless circumstances (incoming pressure, available footprint or budget) do not permit.

For 10μ filtration in typical New York City water conditions, we advise that each gallon per minute of flow rate should have at least 80 cm2 of screen area in a constant pressure application, and ideally about 100 cm2 in a traditional house pump to roof tank application.

Therefore, at a minimum: 100 GPM requires about 8000 cm2 and 400 GPM requires about 32,000 cm2.

Once the max flow rate and filtration degree are known, you can select the correct Omicron model based on the amount of screen area required. When seeking to implement fine filtration, having more screen area is always an advantage.

Important: The ratio of screen area to flow rate is a universal constant and must be maintained for reliable operation.

3. Know the incoming pressure

All screen filtration requires adequate pressure to operate. As a rule, the minimum threshold is higher for finer filtration than it is for coarser. For 25 micron, below 45 psi at the filter inlets becomes risky for reliable operation. For 10 micron, figure a minimum of 58 psi. Filters running off net street pressure include a flush line pump to boost pressure during the critical flush cycles when pressure is critical), which boosts pressure by about 8 psi.

A solution to increasingly common low pressure environments is being adopted with rapidly growing frequency by the engineering community: Locating the filter downstream of the house pumps, thereby leveraging much higher pressure to support reliable 10 micron filtration. Omicron offers high pressure systems to accommodate this option. Up to 150 psi, no special build is required. Above 150 psi, we offer two versions: PN16 for up to 230 psi, or PN25 for up to 360 psi. High pressure builds are especially useful to accommodate installation in equipment rooms now often located several floors above grade, in response to flood zone considerations.

Additional Features to be specified:

Once the above three values have been determined, you will want to further specify your filtration system as noted below.

Orientation: All models are available as horizontal (H) or vertical (V).
Most common orientations are V for the 5300 (smallest), and H for the others (8000 - 21300). Specify based on most efficient use of available space.

Housing Material: All 316L stainless or coated carbon steel.
Nearly all filters we supply today are ordered in 316L stainless. Nothing beats 316L for longevity. However, the quality of Omicron in CCS is outstanding. If cost reduction is an imperative, please note savings are about $6000 / filter by using CCS instead of 316L (depending on size of the filters).

Configuration: Single or Twin
All systems are modular in design thus may be manifolded as duplex, triplex, quad etc. Most are available in twin parallel, manifolded and skidded. Twin configurations permit higher flow rates, redundancy, or a combination of the two.

For example, if the max flow is 400 GPM, the project may call for a twin parallel configuration in which either filter can accommodate 400 GPM. In this case, specify a twin system with twice the rated capacity (or nearly so) of the max system flow.

Flush Line Pump: Yes or No
By default, systems supplied from net street pressure include a flush line suction pump to assure adequate pressure during backwash cycles. This pump is redundant in high pressure and other applications where the incoming pressure is assured to exceed 70 psi. The suction pump has no impact on the overall footprint of a skid.

Failsafe bypass: Yes or No.
All systems are supplied with bypass valves. We recommend including failsafe versions (at a modestly higher cost) so that in the event of a power failure the filter will revert to bypass, and the domestic water supply to the building will not be compromised.

Check Valve: A check valve is essential to prevent backflow that can severely damage the screen(s).
We offer to include the check valve on the skid integrated with the filtration system.

Other Features:

• Operation voltage: 460V AC / 3ph / 60Hz or 208V AC / 3ph / 60Hz
• Max temperature of water to be filtered: Default 120 deg. F max or higher
• Control panel: Default Omicron Touchscreen Type 1 (with HMI interface) or VE to simpler panel
• Flange size: Default 6”. 2” to 14” available as required.

Here is an example of a complete specification of a building water filter.  We highly recommend referencing the minimum screen area required to support the max flow rate / micron rating.  (Can be included as a column in the block or as a separate line item per below.)

For an example of an Omicron Master Spec, please click here

Complete List of Omicron Models

The most commonly specified solutions are in bold.  If you are looking for a specification and do not find the corresponding Engineering Specifications PDF, please use the Omicron Selector to request one.