In the procurement process of HEPA/ULPA filters, faced with numerous suppliers and their elaborate product brochures, how can the buyer see through marketing rhetoric and quickly discern their true technical expertise and professionalism? The answer lies not in listening to what they say, but in asking insightful and relevant questions.
Below are five crucial “soul-searching questions” that can effectively help you evaluate a supplier’s technical capabilities, leading to a more informed decision.
Question 1: “Does your company perform MPPS testing on a unit-by-unit scan or sampling?”
Purpose: To determine the baseline of quality assurance.
A professional supplier’s answer: They will clearly explain their testing strategies for different levels and applications of their product lines. For example, for high-level filters used in critical areas (such as H13 and above), they will explicitly commit to performing a full MPPS leak scan on each unit and provide traceable test reports.
Beware of vague answers such as “Our products all meet standards” or “We use random sampling to ensure quality.” This often means they cannot guarantee that every critical filter leaving the factory has undergone the most rigorous integrity testing.
Question 2: “Can you provide a complete resistance-dust holding capacity curve for this filter model?”
Purpose: To assess their transparency regarding performance data and product energy consumption.
A professional supplier’s answer: They can immediately provide a curve showing the relationship between resistance and dust holding capacity, measured by a third-party laboratory or their own precise experiments. This chart allows you to accurately predict the energy costs and optimal replacement time over the filter’s lifespan.
Beware of answers that only provide an isolated “initial resistance” value and claim “long lifespan.” This exposes a lack of in-depth testing data or an unwillingness to disclose true performance.
Question 3: “In your tests, what was the actual MPPS point (in nanometers) for this filter?”
Purpose: To verify the accuracy and sincerity of their testing.
A professional supplier’s response: They can clearly state the typical particle size range of the MPPS point for this specific product model (e.g., “Our filter media typically has a stable MPPS between 0.10-0.15 microns”). This proves they have truly conducted a full particle size scan, not just tested the standard 0.3μm.
A response to be wary of: A vague answer like “0.3 microns” or “according to the standard.” This suggests they may simply be mechanically meeting standards, lacking in-depth research into the unique performance of their product.
Question 4: “How does the filter’s efficiency decrease with respect to MPPS particle size before reaching final resistance?”
Purpose: To investigate the performance stability throughout the product’s lifecycle.
A professional supplier’s response: They can explain how their filter media and structural design ensure stable or even slightly increased efficiency (dust load effect) during dust collection, and may provide relevant data to prove that there will be no efficiency decline during the product’s lifespan.
A response to be wary of: Only guaranteeing “factory efficiency is qualified,” being completely unaware of or avoiding any discussion of performance changes during use.
Question 5: “During our production process, we encounter [specific contaminants, such as oil mist /metal dust]. Will this affect MPPS and filter lifespan?”
Purpose: To assess their application experience and ability to solve practical problems.
Professional supplier’s answer: They will delve into the specific characteristics of the contaminants and analyze their impact from a technical perspective. For example, they might suggest: “Oil mist can reduce the efficiency of glass fiber filter media. We recommend considering filter media with oil-resistant coatings or usingelectret materials, but be aware of the risk of electret degradation under specific chemical environments.” This demonstrates their extensive application knowledge.
When you can ask these five questions, your role has subtly shifted—you are no longer a passive price taker, but a co-definer of value. Frankfurt-based filter supplier Trenntech is a practitioner of this philosophy. We strictly adhere to these standards in our daily production, striving for excellence to manufacture products of superior quality—because we deeply understand that only in this way can we become your long-term trusted technical partner.