Envirochem visited the headquarters of the international steel building manufacturers and construction organisation Reid Steel to monitor particulates and VOC’s from an exterior extraction stack during paint spraying of steel girders to identify if the stack is effectively removing these compounds
Envirochem attended the site in Christchurch and with the assistance of the Quality, Health, Safety and Environment Manager identified two sampling points on the stack where emission testing could be carried out. Due to the height of the stack, a Mobile Elevating Work Platform (MEWP) was used to gain access. This was located on the side of the building above head height, we ensured 'working from height' safety precautions were followed by wearing a fall arrest system and appropriate personal protective equipment (PPE). A method of isokinetic sampling was used which involved the connection of a series of probes to the sampling point along with a custom built pumping system for the particulate sampling, static pressure and transport velocity readings; and an SKC sampling pump for the VOC sampling. The test procedures are based on the emission monitoring method described in the Environmental Protection Act 1990 Technical Guidance Notes M1 & M2. Gravimetric Analysis followed the isokinetic sampling using equipment conforming to BS9096:2003. Duct velocity and particulates were measured orthogonally through the stack with the flow rate being adjusted to maintain isokinetic conditions. After gravimetric analysis, the exposed filters are digested in aqua regia and analysed by inductively coupled plasma optical emission spectrometry (ICP-OES) (Varian Vista MPX axial ICP-OES).
Alongside this, VOC’s were monitored by using an SKC sampling pump, a known volume of air is pumped and any VOC’s are collected on an exposed charcoal sampling tube. The charcoal was subsequently desorbed into carbon disulphide and analysed by gas chromatography (GC) (Thermo electron focus GC with FID) according to MDHS 88.
The results of the emission monitoring and analysis can be used to inform environmental permits set by local authorities.