# Cartridge Filter Housing Configurations: Multi, High-Flow & Sanitary Compared

> Compare single, multi-cartridge, high-flow and sanitary filter housing configurations — flow rate, cartridge count, materials and ASME code, with ERE's RKI and Shelco housing families.

- **URL:** https://www.ereinc.com/blogs/field-notes/cartridge-filter-housing-configurations-multi-high-flow-sanitary-compared

Choosing between a single, multi-cartridge, high-flow or sanitary filter housing comes down to three numbers: your peak flow rate, how often you can afford to stop the line to service it, and whether the application is food, pharma or general industrial. This guide compares all four configurations against ERE's own RKI and Shelco housing families, so you can size the right one before you request a quote.

**Key takeaways**
- Single-cartridge housings suit flows under roughly 20 GPM; above that, you're choosing between multi-cartridge and high-flow configurations.
- Multi-cartridge housings scale by cartridge count (4 to 52 cartridges); high-flow housings scale by using fewer, larger-diameter elements instead.
- "Sanitary" means 316L electropolished construction, FDA-grade gaskets, and sanitary ferrule connections — required for food, beverage, pharma and cosmetics production, not just a marketing term.
- Housings above a certain size and pressure fall under ASME pressure-vessel code, which affects both the housing you can buy and how your facility must maintain it.

## Table of Contents
- [What's the Difference Between Single, Multi-Cartridge and High-Flow Housings?](#difference)
- [How Many Cartridges Do You Actually Need?](#how-many)
- [When Do You Need a High-Flow Housing Instead of More Cartridges?](#high-flow)
- [What Makes a Filter Housing Sanitary or High-Purity?](#sanitary)
- [Do You Need an ASME Code Housing?](#asme)
- [How Do You Choose the Right Configuration?](#choose)
- [Frequently Asked Questions](#faq)

## What's the Difference Between Single, Multi-Cartridge and High-Flow Housings?

A single-cartridge housing filters through one cartridge and suits the lowest flows; a multi-cartridge housing adds surface area by holding several cartridges in parallel; a high-flow housing gets the same result with fewer, physically larger elements instead of more small ones. All three do the same job — trap particulate as liquid passes through — the difference is how they add filtration surface area as flow requirements grow.

 | Configuration | Typical flow range | Cartridge count | Best fit

 | Single-cartridge | Up to ~20 GPM | 1 | Small process lines, point-of-use, low-volume batch work

 | Multi-cartridge | Roughly 20–300+ GPM | 4 to 52 | Mid-to-high volume process water, chemicals, coolants

 | High-flow | Roughly 50–500+ GPM | 1 to 12 large-diameter elements | High volume with infrequent change-outs, fewer service points

ERE's [CSF Series](/products/csf-series) single-cartridge housing is the entry point for this comparison — rated to 300 PSI at 200°F, with 3/4" or 1" connections and a quick-locking ring nut closure, it covers flows from about 7 GPM (CSF-78) to 21 GPM (CSF-90) on a standard 25-micron wound cartridge. Once a process needs more than that, you're choosing between the multi-cartridge and high-flow paths covered below. See ERE's full [cartridge filter housing range](/collections/cartridge-housing) for the complete lineup.

## How Many Cartridges Do You Actually Need?

Multi-cartridge housings scale in fixed steps — 4, 5, 7, 12, 22, 36 or 52 cartridges — because each added cartridge adds a fixed amount of filtration surface area at a given micron rating, which is what actually sets your maximum flow before pressure drop climbs too high.

## The RKI and Shelco Multi-Cartridge Families

ERE's [4FOS & 5FOS Series](/products/multi-cartridge-housings-4fos-5fos-series) is the entry point for multi-cartridge work: 304L or 316L stainless construction, 2" MNPT connections, and a band clamp or swing bolt closure rated to 150 PSI at 300°F, holding four or five double-open-ended (DOE) cartridges up to 2¾" OD. From there, the same construction scales up through the 7FOS, 12FOS and 22FOS series to ERE's [36FOS & 52FOS Series](/products/multi-cartridge-housings-36fos-52fos-series) — the top of the range, holding up to 52 cartridges on 3"–4" flanged connections for the highest-volume industrial lines.
- Water treatment and process water filtration
- Chemical processing
- Food and beverage production
- Inks, paints and coatings
- Coolant filtration
- Pulp and paper

As a rule of thumb: if your target flow rate divided by the per-cartridge flow rating of your chosen micron level lands you above 4–5 cartridges, you're already in multi-cartridge territory — the question becomes how many, not whether.

## When Do You Need a High-Flow Housing Instead of More Cartridges?

You need a high-flow housing when the real constraint is change-out frequency, not raw filtration area — one large-diameter high-flow element can replace a dozen small cartridges and needs to be swapped far less often.

ERE's [HFE Series](/products/high-flow-housings-hfe-series) is built around a single high-flow element (6" nominal diameter x 23" length) with a V-band clamp for fast push/pull cartridge changes and inside-out flow that retains contaminant inside the cartridge during removal — a meaningful difference for operators who don't want to handle a saturated element. It's rated to 150 PSI at 300°F on 1"–2" connections, with an optional NSF 61 coating available for brackish or seawater service.

For higher-volume lines, the same high-flow concept scales up through ERE's 1HF & [1UHF Series](/products/high-flow-housings-1hf-1uhf-series) to the multi-element [3, 4, 7 & 12 HF & UHF Series](/products/high-flow-housings-3-4-7-12-hf-uhf-series) — combining several large-diameter elements in one housing for facilities that need both high flow and infrequent service intervals.

The trade-off is straightforward: multi-cartridge housings cost less per housing but need more frequent service across more cartridges; high-flow housings cost more per element but cut the number of change-outs and the labor that goes with them.

## What Makes a Filter Housing Sanitary or High-Purity?

A sanitary filter housing uses 316L electropolished stainless steel, FDA-grade gaskets, and sanitary ferrule (Tri-Clamp style) connections instead of standard threaded or flanged fittings — the combination that lets a housing meet food, beverage, pharmaceutical and cosmetics cleanability requirements.

ERE's Shelco [MicroVantage™ HPI Series](/products/high-purity-sanitary-housings-microvantage-hpi-series) holds four to fifty cartridges in an electro-polished 316L shell with EPR (FDA-grade) gaskets and universal cartridge connectors, rated to 150 PSI at 300°F with ANSI flanges standard and sanitary ferrules available as an option. The related [MicroVantage Sanitary SFH Series](/products/high-purity-sanitary-housings-microvantage-sanitary-sfh-series) is built specifically around sanitary-ferrule connections for lines that need to meet washdown and clean-in-place expectations without a flanged fitting to trap residue.

These housings serve ERE's food, beverage, pharmaceutical, cosmetics and electronics customers — segments where a standard poly-coated industrial housing, however well-built, doesn't meet the surface-finish and connection standard the application demands.

## Do You Need an ASME Code Housing?

You need an ASME code housing whenever your jurisdiction's pressure-equipment regulations classify your housing's size and operating pressure as a regulated pressure vessel — which is common on the largest multi-cartridge housings, not the smaller in-line units.

Pressure equipment in Canadian workplaces is generally expected to be designed, installed and maintained in accordance with the applicable pressure vessel code, alongside the facility's other health and safety obligations — [CCOHS' process safety management guidance](https://www.ccohs.ca/oshanswers/hsprograms/processsafety-management.html) lists pressure vessel codes explicitly among the legislation equipment must be maintained against. ERE's Shelco [USF Series](/products/asme-code-usf-usb-housings-usf-series) and [USB Series](/products/asme-code-usf-usb-housings-usb-series) are built to ASME code specifically for facilities where that classification applies, holding four to fifty-two cartridges with swing bolt closures and knife-edge seals on 3"–4" flanged connections.

The stainless plate and sheet used in these housing shells is typically specified against a recognized materials standard — [ASTM A240/A240M](https://www.astm.org/Standards/A240.htm) covers chromium and chromium-nickel stainless steel plate, sheet and strip for pressure vessel applications, the same class of material used across ERE's 304L/316L housing range.

## How Do You Choose the Right Configuration?

Choosing a cartridge housing configuration comes down to four checks: your peak flow rate, your tolerance for change-out frequency, your application's cleanliness requirement, and whether code compliance applies at your size.
- **Establish peak flow rate, not average.** Size against the highest GPM the line will actually see — undersizing here is the single most common cause of premature pressure drop and early cartridge fouling.
- **Decide multi-cartridge vs. high-flow.** If frequent service visits are acceptable and budget is the tighter constraint, multi-cartridge wins. If labor and downtime are the tighter constraint, high-flow's fewer, larger elements usually pay for themselves in reduced service calls.
- **Confirm whether the application is sanitary.** Food, beverage, pharmaceutical and cosmetics production need the 316L electropolished, sanitary-ferrule construction — general industrial water, chemical and coolant filtration typically doesn't.
- **Check whether ASME code applies.** Larger, higher-pressure multi-cartridge housings are the ones most likely to fall under a pressure vessel code at your facility — confirm with your provincial regulator or engineer before ordering if you're near that size threshold.

ERE sizes every housing quote against these four checks — [request a quote](/pages/request-a-quote) with your flow rate, application and any code requirement for a specific recommendation.

## Frequently Asked Questions

## What's the difference between a multi-cartridge and a high-flow filter housing?

A multi-cartridge housing adds flow capacity by holding more standard-size cartridges in parallel (4 to 52); a high-flow housing adds capacity with fewer, physically larger-diameter elements instead, which cuts the number of change-outs needed at the same flow rate.

## How many cartridges does a multi-cartridge housing hold?

ERE's multi-cartridge range scales in fixed steps from 4 or 5 cartridges up to 52, depending on the series — the right count depends on your target flow rate divided by the per-cartridge flow rating at your chosen micron level.

## What makes a filter housing sanitary?

Sanitary housings use 316L electropolished stainless steel, FDA-grade gaskets, and sanitary ferrule connections instead of standard threaded or flanged fittings, meeting the cleanability standard food, beverage, pharmaceutical and cosmetics production requires.

## Do cartridge filter housings need to meet ASME code?

It depends on size and operating pressure — larger multi-cartridge housings are more likely to fall under a regulated pressure vessel code. ERE's USF and USB Series are built to ASME code specifically for facilities where that classification applies.

## Can ERE supply cartridge filter housings for food and pharmaceutical applications?

Yes. ERE's Shelco MicroVantage sanitary and high-purity housing lines are built for food, beverage, pharmaceutical, cosmetics and electronics applications, with electropolished 316L construction and FDA-grade gaskets.

## Related articles
- [uPVC vs. Stainless Steel Filter Housings: Chemical Compatibility & Selection Guide](/blogs/field-notes/upvc-vs-stainless-steel-filter-housings-chemical-compatibility-selection-guide)
- [Industrial Filter Cartridges: How to Choose the Right Type and Micron Rating](/blogs/field-notes/industrial-filter-cartridges-how-to-choose-the-right-type-and-micron-rating)
- [Bag vs. Cartridge Filtration: Which to Use](/blogs/field-notes/bag-vs-cartridge-filtration-which-to-use)
- [Multi-Bag vs. Single-Bag vs. Duplex Filter Housings: Which Configuration Do You Need?](/blogs/field-notes/multi-bag-vs-single-bag-vs-duplex-filter-housings-which-configuration-do-you-need)

**Need help choosing a cartridge filter housing configuration?**

ERE Inc. has been Canada's environmental and industrial equipment specialist for 30+ years. Talk to a real engineer about your flow rate, application and code requirements.

 [**→ Request a Quote**](/pages/request-a-quote) | [1-888-287-EREC](tel:+18882873732) | [Browse Cartridge Filter Housings](/collections/cartridge-housing) | [sales@ereinc.com](mailto:sales@ereinc.com)

*Lire en français : [Configurations de boîtiers de filtration à cartouches : multi-cartouches, haut débit et sanitaires comparés](/blogs/perspectives-securite/configurations-de-boitiers-de-filtration-a-cartouches-multi-cartouches-haut-debit-et-sanitaires-compares)*