Camfil filters to protect employee of Mercedes Benz Head Quarter in Beijing from heavy smog
When outdoor PM2.5 @ 374μg/m3 – what status of indoor air quality it could reach if without any air purifier assisting? Mean value less than 4μg/m3 - reported by the inspection team for Mercedes Benz HQ Towers Beijing, combined of representatives from MEP consultant, property management, building developer, renter, and Camfil.
After over 10yrs operation, Mercedes Benz planned to retrofit its HVAC system of Beijing HQ building, so as to prevent its IAQ from heavy SMOG in Beijing. Camfil won this tender at Q4 2017 - including design and frame installation of 100+ new & renewed MAU/AHUs, as well as filter supply in the following 2 years, with total amount over 2.5mRMB. As a return, Mercedes Benz required mean value of indoor PM2.5 no higher than 35μg/m3 without assistance of any inner device, and filters should be replaced immediately once any pressure switch and/or any indoor PM2.5 indicator alarms. This is a brand-new challenge to Camfil Comfort team.
After site inspection and HVAC schematic diagram study, we found that the buildings were equipped with VAV system, which means all of air ventilation comes from air handling units, and indoor air exchange rate is up to 8 times per hour. Before entering the room space, the fresh air will go through MAU and then mixed with return air in AHU. Therefore, the fresh air with SMOG could be filtered by at least 4 stages of filters in both MAU and AHU. It may be feasible to achieve the goal of PM2.5 by controlling air filtration of AHU/MAU tightly and properly.
To accomplish this mission, we also considered a few of protective measures:
1. G4/F9 (Hi Flo) in MAU, G4/F8 (S-Flo) in AHU. MAU will encounter outdoor air directly, in which Hi-Flo will have more dust capacity. But AHU’s ESP is limited, so we have no choice but to put synthetic bag filter, which is cheaper and could be replaced more often.
2. Fine filters will be locked by bolts instead of clips, to prevent air leakage as much as possible.
3. Frames are made by stainless steel, to make sure its strength and reliability.
4. Clean the chamber of AHU/MAU every time when filters are replaced.
5. Remind consultant and owner to clean the ducts, ensure air tightness of doors, windows and AHUs, note the effectiveness of air ventilation in each corner of indoor space, etc.
After production and installation at our full stretch, followed by 3 months trial, all stakeholders gathered on March 14 2018 to test the performance of Camfil’s solution. The result exceeds our best expectation – mean PM2.5 was 3.9 μg/m3, @ 5 points per floor selected. It has been beyond WELL certification, the most restrict standard in China market. Every participant was satisfied and signed with their approval delightedly. Because of the stable and outstanding performance, Camfil was also awarded Caterpillar Tower, the building next to Benz in Nov. 2018, with the same solution.
This success proves that Camfil China can enter Comfort market with a new angle – IAQ guarantee. WELL-certified Mercedes Benz China HQ helps convince more customers and partners with Camfil solution. In the original mind of Chinese, the filter efficiency should be as high as HEPA to reach and maintain indoor air quality at physically healthy level. Trial of Benz project demonstrated an efficient and economical way.