1. Then on our Project Specification we have specified that inlet stack shall be minimum of 4500mm high and shall be suitably self supported and fitted with a flexible joint at the fan suction.
Contractor replyed back that the requirement of minimum 4500mm high for inletstack is not applicable considering the purpose of air purge fan, and the air intake duct / stack will be designed by vendors standard.
what is your view on this.
2. In our contract we said contractor shall comply with the specification and provide the required air flow venturi for purge air.
contractor replyed backj saying that venturi is not required since the main purpose of the fan is for purging during start -up only and will not be used during operation. The application for venturi is used to measure the actual air flow coming from the combustion air for maintaining the air/fuel ratio and is generally done for Forced Draft system. It means that the purge air does not need to be measured and controlled.
what is your view on this
3. We said that the vendor shall demonstrate that their design will not result in the maximum metal temperature exceeding the process fluid temperature by more than 56 deg C in the convection section and by more than 44 deg C in the radiant section
contractor replyed back that the process feed of the heater are designed with lower temperature. In this condition the above requirement is not applicable and contractor will follow the data sheet with maximum tube metail temperature of 710 DegF in order to avoid corrosion on tube materials
What is your view on this