Invitation To Tender For Supply Of Skilled Labour, Approved Materials And Other Accessories To Carry Out Non-Comprehensive Air_Conditioning And Mechanical Ventilation (Acmv) And Air Purifier Planned Preventive Maintenance Service For Senior Day Care, Active Ageing Centre, Community Social Service, Family Medicine Clinic, Nursing Home And Hq (Base 2 Year, Option To Renew 2 Year)