Frequently Asked Question on CAR 2014 and Chimney Construction.
FAQ 1 - DO I NEED TO COMPLY TO CLEAN AIR REGULATION 2014 ?
The emission of pollutant to the environment is a straight forward understanding that it will be needing effective control mechanics thats ensure the emission does not cause environmental impact. However, the entity which generate the emission via its commercial activities must always be able to see that in that manner in order to be able to accountability in establishing the effective control mechanism. Most of the time, the need to comply to the statutory regulation seems to take precedence rather than applying the engineering common sense. Perhaps at this point, these logical thinking is only applicable to anything which give profit in return. Health, Safety and Waste means needs to be purely based on regulatory adherence otherwise one can exempt themselves from performing the duty under the pretext of ignorance. I guess this is why we have to keep reeducating ourselves from this very unfortunately oblivious ignorance.
Regulation 3 in the CAR 2014 address this matter not in the smartest way but somehow rather makes a point. It has given fuel burning equipment as an example as I guess we all will know that combustion process will generate pollutants. The other statement about processes which produces pollutant in very subtly mentioned. The best way for us to understand this is, any process which has potential to emit aerosols (mist, fog, particulate matter, fibers, smokes, fumes) vapour and gaseous.
As to make the entire process much more methodological take note of generating or dispersion energy to anticipate the potential physical form of the airborne hazard. For example the thermal energy increase will cause sublimation and evaporation generating fumes and vapours. Meanwhile the decrease in the energy will cause condensation forming fumes and fogs.
The likelihood of air borne hazard emission is very much likely depending on the condition and characteristics of the material. These specifics ranges :-
Amount of chemicals
Exposure duration
Exposure frequency
Generating / Dispersion energy (as mentioned above)
Physical form
Volatility (for gaseous and vapor) - vapor pressure, boiling point, exposed surface area
Aerodynamic diameter (aerosols)
Moisture content (particulate matter and fibers)
FAQ 2 - WHAT I NEED TO DO AS COMPLIANCE TO CLEAN AIR REGULATIONS ?
The fundamental steps to be taken prior to deploying the engineering control is the identify the airborne hazard and define its characteristics as discussed above. Once these fundamentals steps are established, next is to decide the choice of ventilation system. A local exhaust ventilation system which captures and removes the airborne hazard at the point of emission is to be prioritised as the first choice of approach due to its efficiency of removal. The integration of the general ventilation the LEV System is very much depending to the efficiency of the LEV hoods to be chosen. If the LEV hood is to encapsulate and capture 100% of the airborne hazard, and no specific means of make up is required, the General Ventilation systems can be bypassed. However, if the negative pressure rating in the room becomes extremely high due to installation of several exhaust hoods being placed in one room, then the make air supply and room pressurisation must be very well defined.
The design steps at this point is to be done by adopting a good engineering standard reference which will define the range of capture velocity, accurate design equation with all the factors involved based on the choice of hood or ventilation system being made. A General Ventilation will require Air Change Per Hour, Mixing Ratio, Effective Placement of exhaust grills and diffusers, room pressurisation and etc to be added as apart of the design parameters. A LEV system will require selection of effective geometrical shape as its hood for encapsulation of the emission. If encapsulation is not to be done, then an exterior hood create air displacement towards its opening must be chosen. There are many standard available ranging from ASTM, NFPA and etc to simulate the design numbers but one of the most relevant standard to be adopted will be the Industrial Ventilation A Manual of Recommended Practise for Design 30th Edition by ACGIH - American Conference of Governmental Industrial Hygiene. The guideline for industrial ventilation system design or defined as Air Pollution Control System by Department Environment has also adopted the excerpts from this standard reference. The design which is to used any standard reference rather than having a guesstimated approach will enhance the reliability of the system. As to add the accountability the design works is to be endorsed by a Professional Engineer register with Board of Engineers in Malaysia. This step will further ensure the design exercise are of certain standard and has been verified by a professional. These design documents which is validated based on an acceptable standard then is to be vetted by the Department of Environment. Upon proper verification and updating any need of improvement in the design, the ‘approval’ is to be given as the green light for construction. At this point the approval will serve as the construction ‘blue print’ for the contractors to adhere in their installation. Any significant changes from the approved approach will need review in calculation especially its system static pressure.
FAQ 3- WHAT I NEED TO DO AFTER CONSTRUCTION ?
The design work is never complete without the execution of the testing commissioning exercise. The purpose of the design simulation is to ensure the factors used in the design equation are met in the testing commissioning stage. This is the reason the need to use of the acceptable design standard is specified in the compliance requirements. The testing and commissioning exercise is to test the design empirical parameters provides the desired actual results. For example if the design basis is 100 fpm capture velocity, the actual testing during commissioning must be able to meet the 100 fpm. All necessary action such as damper control and air flow balancing must be done to meet the basis. If the numbers are not achieved, then the air concentration test can be done to check the removal efficiency of the airborne hazard to commission. However, the root cause of the failure must be done as a proper use of acceptable standard will results commissioning test to meet the design numbers.
Once a good testing and commissioning exercise is completed meeting the design parameters, the data taken at the actual operation setting must be used as the baseline peak performance. The peak performance is the upper limit of the operation range. The lower limit will be the lower limit of the acceptable condition which is also to be derived in the design specification. The limits are low limit of capture velocity, transport velocity, filtration velocity and efflux velocity. The actual operation running below this limit will be detrimental. Periodic testing in the form of performance monitoring must be established as the preventive maintenance protocol. It is the duty of the system provider to train the user and their maintenance team on conducting the performance monitoring and maintenance (both preventive and predictive).
As for the compliance requirement, the condition of the DOE approval is to establish an effective performance monitoring. This performance monitoring which is to be established must clearly address the need to gauge the operation performance to be within the acceptable limits. As apart of the CAR 2014 Regulation 7 requirement, upon successful commissioning exercise the As Built Drawings, 30 days of performance monitoring data complete with a Declaration form stating the system was build as per the design parameters and will run within the acceptable limit must be made to the DOE office. It is also becoming a common practise to add a baseline chimney emission monitoring to declare further proof that the system was designed very effectively and its baseline test data are sowing all numbers within CAR 2014 permissible limit values.
FAQ 4 - HOW SOON DO I NEED TO CONDUCT CHIMNEY EMISSION MONITORING AND HOW FREQUENT ?
Prior to the Clean Air Regulation revision in 2014, chimney periodic monitoring was carried out in quarterly basis. However this requirement was dropped in the 2014 regulation. Subjective to the toxicity and severity of the environment impact the pollutant / air borne hazard can cause. The high toxic pollutant based on certain process required continuous monitoring meanwhile subjective to the dust load the fuel burning equipment chimney discharges are to be tested from 2 to 4 times a year. The non stipulated part of the requirement here is the stability of the emission pollutant characteristic and control equipment reliability. In the event the control equipment could not provide a steady state emission results which exceeds the permissible limit or does not generate adequate efflux velocity for effective plume rise and dispersion, the frequency of the periodic testing must be increased until a good performance monitoring exercise can justify that the instability are well addressed with the good preventive maintenance exercise or any other control means.
As for the baseline chimney emission requirement, the maiden test must be conducted 3 months after the operation is kicked off and must be done before the 6th month since operation is begun. However as mentioned in previous segment most of the DOE office requires the baseline report during the declaration submission. However, the testing provider must ensure the baseline chimney emission is taken during the actual operation condition and not during the dry run. The baseline emission test must clearly address the effluent velocity, the flow rate and also the pollutant’s concentration gauged based on permissible limit listed in CAR 2014. If any of the particular pollutants are not listed in CAR 2014, then the baseline concentration results must be taken as the criterion to be compared periodically on its tremendous increase. The ambient air monitoring results can also be added to justify that the stationary source (chimney) discharge does not impact the ground level concentration. However, this requirement is not mentioned in the CAR2014. The suggestion is made based on the fundamental function of the chimney which is to ensure the pollutant discharges undergoes plume rise / stack effective height, effective dispersion and do not undergo any downwash increasing the ground level concentration within the vicinity of the erected chimney.
The chimney emissions results must incorporate both the pollutant concentration and efflux velocity. There are misunderstanding by some auditors and HSE personnel that efflux velocity does not need to be added in the chimney emission monitoring as it is not mentioned in CAR 2014. The false comprehension as such takes place due to a very poor understanding of industrial ventilation system and the stereotype thinking to have complying results of the statutory regulatory body. Actually the intention to have complying results is good but the lack of understanding the objectives of any monitoring will defeat the whole purpose of the assessment. A chimney is one of the component of an industrial ventilation system. The function of the chimney is to generate vertical discharge outside any turbulence region within the building envelope so that adequate buoyancy can be achieved to generate plume rise and effective dispersion. In lay man term any residual pollutant is to undergo an upward dispersion and dispersed at elevated trajectory without moving towards the gourd while its get diluted along the travel path. An effective stack height can only be achieved with adequate vertical momentum in the form of effluent velocity. A good efflux velocity can only be maintained with operation of the system within the acceptable limit of flow rate. Deterioration of flow rate outside the acceptable range will diminish the capture velocity, transport velocity and filtration velocity which will have its impact to the quality of air being discharged at the chimney. As per this fundamental functionality of the ventilation system, one must remember to always start the chimney emission assessment with the efflux velocity first.
FAQ 5 -WHY DO I NEED TO CONDUCT PERFORMANCE MONITORING ?
The entire operation of the ventilation system runs with the fundamentals of capturing, conveying, cleaning and releasing. The whole system runs based on the basis of air flow being generated at the suction point to encapsulate, propagate and remove the airborne contaminant. The primary objective of the ventilation system is derived at the suction point or hood in the case for local exhaust ventilations system. The system flow rate is derived based on the capture velocity, capture distance and density correction of a local exhaust ventilation system. The system flow rate of a General Ventilation System is based on air change per hour of an enclosure. A designer must carefully choose the choice of ventilation system and its applicable flow rate equation based on acceptable standard reference. Once this design flow rate is derived, the rest of the component which is the duct, air cleaning device, chimney and the fan is designed based on this design flow rate. This is why during the commissioning stage the capture velocity or air change per hour is to be tested to check if the primary objective of the design parameter is met. Once the capture velocity or air change per hour is within the designed range, the rest of the components are tested and a baseline data is to be recorded. As it can be seen in the illustration above, the baseline data is also illustrated as the peak performance. A newly installed system will have very minimal resistance build up across the system and low wear and tear. This condition will generate the peak performance. This peak data is to be taken as the point of reference to maintain the system performance around the baseline condition. A range of deterioration can still be allowed until it reaches a lower limit to minimise idle time for preventive maintenance. For example the design factor of a Local Exhaust Ventilation System can be made based on a range of capture velocity between 500~2000 fpm for high energy dispersing air borne hazard emission at the point of generation. The design flow rate can be set at 2000 fpm. During the baseline test this number will serve as the upper limit meanwhile the 500 fpm can be made as the lower limit. Once a baseline test is conducted and user has been well trained on how to record these data, the user would be able to plot the deterioration of the flow rate from the peak point. The deterioration of flow will happen due to several factors ranging from drop in fan speeds caused by wear and tear of drive system (bearing and belt), misalignment of fan impeller due to disposition of coating on blades causing bearing failures, increase of clogging in air cleaning device, blockage of face areas at the hood due to deposition of particulate matter, change in make up air in the enclosure and etc. Scenarios as such will increase the static pressure losses and will reduce the system flow rate. The system flow rate will decrease the capture efficiency. The moment the deteriorating number reaches 500 fpm, the system and its associated process can be schedule for preventive maintenance. Once the preventive maintenance action is accomplished by improving the elements which have caused the dwindling flow rate, the performance of the system can be pushed back to the baseline condition. Right after that the performance monitoring can be resumed diligently and vigilantly to ensure the system operates within the acceptable range. And the moment the operation gets below the lower limit, actions are to be taken to tweak back the performance to the baseline condition. This cyclical phenomenon should be made as the operation and maintenance protocol.
