A filter housing datasheet that says “max 10 bar” looks like a complete answer. It is not. That figure can describe the vessel shell, the weakest connection, or a catalog limit that only holds at room temperature, and each reading leads to a different purchasing decision. For importers, a misread rating can mean a housing that leaks at operating temperature, fails a documentation check at destination, or costs more than the line needs. This guide explains how to read the pressure line on a bag or cartridge filter housing datasheet, how temperature, closures, seals and connections change usable pressure, which documents prove a rating, and what to put in an RFQ so supplier quotes can be compared on equal terms.
A filter housing pressure rating is the highest pressure the finished housing is allowed to see, at a stated temperature, as limited by its weakest pressure-retaining component. Three parts of that sentence matter: “finished housing,” “stated temperature,” and “weakest component.”
Also confirm whether the figure is gauge or absolute pressure (“barg” vs “bara”). Do not assume; ask the supplier to state it in writing.
Datasheets and quotations often put several pressure terms next to each other. They are not synonyms. Kezar Engineering’s explanation of MAWP, design pressure and operating pressure describes operating pressure as a process condition, design pressure as the mechanical design basis, and maximum allowable working pressure (MAWP) as the limit of the completed vessel at a specified temperature. Its worked example, with 10 barg operating, 12 barg design and 13.5 barg MAWP, shows how all three numbers can be correct at once.
| Term on the datasheet | What it describes | Who normally sets it | What a buyer should ask |
|---|---|---|---|
| ضغط التشغيل | Pressure in normal use, in your process | Your process engineer | Normal and maximum values, including pump start-up and valve closure |
| ضغط التصميم | Pressure used for the mechanical calculation | Specified by buyer or manufacturer | Coincident design temperature and whether it is gauge pressure |
| MAWP / rated working pressure | Limit of the completed housing at a stated temperature | Manufacturer under the governing code | Is it on the nameplate, and for which component and temperature? |
| اختبار الضغط | Pressure applied during fabrication testing to prove integrity | Governing code and manufacturer | Request the test record: actual pressure, hold time, date, unit serial number |
| الضغط التفاضلي | Pressure drop across the bag or cartridge | Set by flow, media and fouling | Maximum dP from the bag or basket supplier, not from the housing rating |
The practical rule: maximum operating pressure, including transients, should sit below the housing’s rated pressure at your operating temperature, with a margin your engineer chooses. A housing marked “10 bar” has a 10 bar ceiling; it is not a 10 bar duty housing.
A bag filter housing sees two different loads. The first is line pressure on the shell and cover. The second is differential pressure across the bag, which the perforated support basket carries as the bag loads with solids. The housing rating does not cap the bag’s differential pressure limit. Bag manufacturers specify their own maximum dP and changeout guidance, and the basket design affects what the assembly tolerates. Ask for both.
Pressure rating and temperature move together. The industrial single-bag unit in this range is listed at up to 10 bar and temperatures up to 120°C “when the selected gasket and filter bag materials are suitable,” and the same page names NBR, EPDM, silicone, FKM and PTFE as gasket options. That wording is useful, because it shows the temperature figure depends on seal and bag choice. Read the industrial stainless steel single bag filter housing specification the same way: the 10 bar and 120°C numbers are ceilings for the housing platform, and your actual limit is whichever component fails first at your fluid temperature.
Check these four items when temperature is above ambient:
The weakest-component rule is where most import surprises start. Four areas deserve a direct question to the supplier.
Swing eye-bolt covers are common because they allow full access for bag changes. The domed-cover single bag housing page describes a raised cover secured by swing eye-bolts and a full-opening cover, and the same pressure ceiling applies to the complete assembly, not just the dome. Ask whether the closure, cover seal and bolts were part of the design calculation or test, and whether the unit suits repeated opening cycles.
Entry style does not change the rating by itself, but the connection you pick does. The غلاف مرشح كيس من الفولاذ المقاوم للصدأ ذو مدخل جانبي is offered with flanged, threaded or sanitary connections, and its page notes that temperature limit and chemical compatibility depend on the selected bag and gasket. Threaded ports, tri-clamp ferrules and flanges can each carry different allowable pressures at the same line size. The top-entry bag filter housing is listed with 2″ and 3″ or customized flanged ports and a pressure gauge and vent connection; if you request a custom flange, confirm its rating matches the shell’s.
A flange class number is a designation, not an operating pressure. PipeData’s pressure-temperature rating reference points out that a Class 150 flange is not rated for 150 psi: in carbon steel it is listed at 285 psig at 100°F, falling to 140 psig at 600°F, and stainless steel groups follow their own tables. PipeData is an independent reference that reproduces standard data, so verify the final figures against the current ASME or EN standard. The principle for buyers holds either way: a “PN16” or “Class 150” port on a quote needs a material group and a temperature before it means anything, and the flange rating at your temperature should not be lower than the housing’s rated pressure.
Larger covers and larger port sizes raise the stakes. The multi-bag stainless steel filter housing range covers 3 to 12 bags with 2″ to 8″ flanged connections and accessories such as a pressure gauge, vent valve, drain valve and lid lifting device. On a vessel this size, ask for the drawing or calculation summary that shows how cover and nozzle loads were handled. Check the gauge, vent and drain valve ratings too, because auxiliary fittings are part of the pressure boundary, and choose a gauge range that suits the housing limit.
Unit conversion errors create false confidence. One bar equals about 14.5 psi, so 10 bar is about 145 psi, and 16 bar is about 232 psi. A figure shown as “150 psi” in one listing and “145 psi” in another may be the same 10 bar housing, rounded differently. The nameplate and quotation should carry one defined unit. One MPa equals 10 bar. Older documents may use kgf/cm², close to but not exactly one bar.
Require the quotation to repeat the rating in the unit your destination authority or end customer uses.
The table below uses the housing pages linked in this article, as listed when they were reviewed in October 2026. Listings can change, so confirm every value in the quotation.
| نمط السكن | Pressure as listed | Temperature as listed | What to confirm before ordering |
|---|---|---|---|
| Industrial single bag | 10 بار كحد أقصى (150 رطل لكل بوصة مربعة) | Up to 120°C, depending on seal and bag | Gasket compound at your temperature; unit used on the nameplate |
| Sanitary tri-clamp single bag | 10 بار كحد أقصى (145 رطل لكل بوصة مربعة) | 95 درجة مئوية كحد أقصى | Rating of clamp, ferrule and gasket at line size |
| Domed-cover single bag | 10 بار كحد أقصى (145 رطل لكل بوصة مربعة) | 120 درجة مئوية كحد أقصى | Cover and eye-bolt design basis; opening-cycle suitability |
| Side-entry single bag | ما يصل إلى 10 بار | تصل درجة الحرارة إلى 120 درجة مئوية | Rating of the selected flanged, threaded or sanitary connection |
| Top-entry single bag | 10 بار كحد أقصى (145 رطل لكل بوصة مربعة) | 120 درجة مئوية كحد أقصى | Custom flange rating; gauge range |
| Multi-bag (3–12 bags) | 10 بار كحد أقصى (150 رطل لكل بوصة مربعة) | Not listed on page | Temperature rating; cover and nozzle design basis |
| 20″ Big Blue cartridge housing | Not listed on page | Not listed on page | Pressure and temperature rating, clamp-ring rating, test record |
Two things stand out. First, the bag housings share a 10 bar ceiling but have different temperature envelopes, so “10 bar” cannot be compared without the temperature beside it. Second, a rating can be absent altogether. The 20-inch Big Blue stainless steel cartridge housing page describes a clamp-ring closure and threaded ports but does not list a pressure figure. For an importer, a missing number is a question to put to the supplier before quoting, never an assumption. Do not carry a rating from one product family to another.
It depends on the destination market, the fluid, the size of the vessel and the end user’s requirements. A stated rating tells you what the manufacturer claims. Certification and documentation tell you what has been assessed.
For the European Union, the summary of Directive 2014/68/EU on pressure equipment states that the directive applies to pressure equipment with a maximum allowable pressure greater than 0.5 bar, covers equipment new to the EU market whether made inside or outside the EU, and makes importers and distributors, not only manufacturers, responsible for compliance. A 10 bar filter housing therefore sits above the scope threshold. Whether it needs CE marking and a notified-body procedure, or falls under sound engineering practice with no CE mark, depends on the directive’s classification, which looks at the fluid group, fluid state, maximum pressure and vessel volume. Ask the manufacturer for its written PED classification and the supporting module, not just a CE logo.
Other destinations differ. Some US end users specify ASME BPVC Section VIII code-stamped vessels, and some Canadian provinces may require design registration for pressure vessels. Check requirements with your customs broker, the local pressure-equipment authority or the end customer’s specification, and write them into the RFQ.
The common assumption is that the highest listed pressure is the safest choice. That is not always true. A higher pressure class often means heavier wall and flange thickness, more weld and inspection work, longer documentation and a higher price. If your line normally runs at 3 to 4 bar with a defined relief device and controlled pump behavior, a housing with a clear 10 bar rating and complete test records may serve you better than a more expensive, higher-rated unit. Conversely, a low-priced housing marked “10 bar” with no code reference, no test record and no stated temperature is not equivalent to a documented one, even if the headline number is identical. Choose on documented rated pressure at your temperature, plus the paperwork your market requires, not on the biggest number.
An illustrative scenario (not a real customer case). A buyer receives two quotes for a single bag housing, both showing “10 bar.” Quote A states 10 bar at 120°C with FKM seals, includes a hydrostatic test certificate for each unit, and names the governing design code. Quote B shows “10 bar” with no temperature, no seal material and no test record. The buyer’s process runs at 85°C with a solvent-based coating. Quote A can be checked against the process. Quote B cannot, and a lower unit price may reverse after the first leak, seal replacement or rejected delivery.
Ask the supplier to provide, before purchase order and again with shipment:
A precise RFQ lets suppliers quote the same product. Include:
Send these details with your destination country so the proposal addresses rated pressure, temperature, documents and lead time in one response.
It usually means the housing’s highest allowed working pressure, but only under stated conditions. Confirm the temperature, whether it is gauge pressure, and whether the weakest component, such as the closure, gasket or connection, supports the same pressure.
No. Operating pressure is the process condition, while the rating is the ceiling. Keep maximum operating pressure, including pump start-up and valve closure transients, below the rated pressure at your operating temperature, with a margin chosen by your engineer.
Higher temperature reduces the pressure that metals, flanges and elastomer seals can safely support. A rating is meaningful only with its temperature, and the filter bag or gasket often limits the assembly before the stainless steel shell does.
Ten bar is about 145 psi. Some catalogs round it to 150 psi. Neither figure replaces the nameplate value, so ask the supplier to state the rating in one defined unit and specify gauge or absolute pressure.
No. A flange class is a designation, and its allowable pressure depends on material group and temperature. The flange rating at your operating temperature should be at least equal to the housing’s rated pressure.
It depends on destination, size, fluid and end-user requirements. In the EU, the Pressure Equipment Directive applies above 0.5 bar maximum allowable pressure, then classification determines CE marking. Confirm local requirements before ordering and request the supplier’s written classification.
Request the pressure test record by serial number, showing test pressure, hold time and result, plus the datasheet with rated pressure and temperature and applicable material and conformity documents. Agree on nameplate wording before production.
