Haze updated 08 Jun 23 (last 14 Sep 2019)

We are experiencing hazy conditions in region of Singapore and region.Air quality may drop to unhealthy levels again.This article will address of commerical and industrial building aircon, fan and ventilation design. Hope this will help the Facilities, Aircon Technicians, Engineers and Managers.

Introduction: Air filters, Carbon Filters

Haze particles are unburnt particles, soot. It is made of all odour gaseous molecules, very small, fine to very big particles. Thus prefilters MERV6-MERV10 are effective for big particles, the fine or visible or particles can be removed by at least MERV11 >85%@3-10um,  MERV13 filters 85%@1-3um. Recommended at least MERV14 90%@1-3um. Absolute HEPA are not required in most cases.When haze particles are controlled, the smell odour will be reduced. Further control can be used with Carbon Filters in rolls or Carbon Pleated in direct replacement of prefilters of 1-4"depth

Please consult the operation team or aircon team which is feasible to implement to prevent infeasible or impratical solutions. Air change or volume is important parameter in ventilation to ensure the ACMV equipement functions properly. 

Action Plan Solution

Limit the air intake from outdoor. Close windows and on aircon.

Stay indoors by limiting outdoor activities, wear a face mask to go outdoors if required.

As the souce of contaminated or polluted air comes from outside, for enclosed buildings temporary limit the fresh air intakes, PAU, Doors or windows openings or gaps.

Air Filter Factory -Secondary filters and Carbon filters

We have increasing request from customers during haze as our Singapore factory we will give priority to existing customers and stock limit to required  qty only to prevent unnecessary stockpile by individual.

Carbon Filter Roll media is fast, easy and effective to implement by covering Aircon or intake for immediate solution.

1. ZKG carbon rolls 1.2x20mx10mm, 1.2x20mx3mm.

Recommended MERV14 Secondary filters

The indoor air quality shall be affected by aircon and ventilation design, source of contaminants including  food, furniture, rubbish etc. The recent ISO16890 to replace EN779 relates the indoor air qualtiy with filtration to ePM2.5, ePM10.0 but different suppliers may present it differently. The comparison to one another is similar and does not make an impact. We may be familiar to ASHRAE MERV (EN779) for faster selections.MERV6 (G3) 30%prefilters and MERV14 (F8) 90%secondary filters for the control of haze particle with recommended optional carbon filters to control smell which also recommended in SS553.

ACMV equipment which mostly already have secondary filters with >MERV13 will be sufficient, Any MERV14 secondary filters will do. Ccell is available in 2" and 4" thickness which can  be installed in filter holding frames of AHU.

1. Minipleat Ccells 2" thickness and 4" thickness available in MERV14

MERV14 >90% @1-3um, >95%@3-10um, the best protection against haze.


2. ES65 IF or ES13 IF Interfold Pleated 24x24x2" (595x595x45mm)

can Interchange with all prefilters in AHU, PAU, FCU


3. CARB IF Carbon Pleated 24x24x2" (595x595x45mm)

Interchange with all prefilters in AHU, PAU, FCU



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