Holdfast Training Services Trial Blog

Introduction

I’ve now been in the design office for 2 whole weeks, working in the Interiors/Tenancy Section in the Existing Buildings Department. In summary, we design all mech, elec and hydraulic services for existing building refurbishments, usually office/business fitouts. Overall office work leading up to Christmas has been a little frantic, mainly involving clearing deadlines and getting tenders out for new business for the start of the New Year. I have undertaken a few interim tasks as stated below with my first real project role coming in the form of an animal hospital fitout – kind of apt coming from the PCH project.

Interim Tasks

The following three tasks were given to me as more of a filler and introduction to the types of projects I’ll be getting involved in.

1. Fee Proposal Review. A review of NDY’s fee proposal for the replacement of a generator exhaust. The mechanical contractor originally approached by the client were only a small company and felt the proposal was too detailed and consisted of too much management terminology for the simple requirement. There was nothing wrong with the proposal and we deemed it fit for purpose so advised the client to explain this to the contractor. If they still didn’t agree then we advised them to re-tender to a more suitable one; who could see past the management procedures and policies, that I feel they were deeming too complex.

2. Giving Technical Advice via a Consultant’s Advice Note (CAN). The CAN was for the reprogramming of the BMS in a recent office fitout we had completed where two separate floors were adjoined by a central stair. The CAN gave a technical explanation for the need to consider both floors as one in terms of smoke management in a fire event when creating the fire and smoke cause and effect matrix.

3. Restricted Return Air Path. This consisted of a study of the AHU return air path in a new office fitout where, due to the type of return air system used, being via extract grilles straight in to the ceiling void acting as a large plenum, it was found that obstruction from sections of full-height partition walls were restricting return airflow. We came up with a solution to install a number of transfer grilles through particular sections of the full-height walls. The trade off being potentially increased noise levels for better recirculation.

Short-term Projects

I have just started my first main project, my role being the Project Leader (PL) for the fitout of a new animal hospital. The current space if no more than an empty warehouse serviced by 3 No. Evaporative air-conditioning system linked through flexible ducting (which they seem to love over here). There is also an existing toilet and lighting throughout.

The PL roles sees me being the client facing project manager reporting to a Project Director (PD) who is also doubling-up as the mech technical lead. My boss (also mech biased) has been helping out and accompanied me to my first client meeting and site inspection; he will be on extended leave post Christmas till the end of Jan so has basically helped me get the project rolling.

In terms of detail at this stage our client, Perth Citi Fitout, are the Managing Contractor who have already put together construction force of various subcontractors based on the scope of works from their client, Vetwest. They have Nagel, architects, who have designed the fitout so we have a pretty good idea of what they want. The services are pretty straightforward with the bulk of design work being the mech air-conditioning system.

At present the MC has budgeted for a complete strip-out and new installed system so that’s exactly what we are going to design. We did see if the existing evap units might be useable but decided pretty quickly to replace them. This was mainly based on the poor effectiveness of evaporative cooling in high humidity conditions. Granted that the Perth climate conditions produce mostly dry heat but there are occasional humid spells in the winter months, which realistically would only offer a small delta T due to evaporation becoming more difficult proportional to the water content present in the air.

The MC issued us a concept mech layout but from our meeting and discussions over the number of HEPA filtration units required we went away and conducted our own research. The two main points were, the requirement for a grease trap for the wastewater drainage system and HEPA filtered units to be installed in all locations where animals would be.

Both of these are being investigated and I am awaiting specialist confirmation. My initial thoughts being thus:

Grease Trap. After stakeholder engagement it was identified that the areas where animals (primarily dogs) will be kept for long periods of time, the kennels and cages are fitted with special chemicals that soak up urine and water content in faeces. These are regularly cleaned out and disposed of in specific excrement waste bags so it is my view that normal wastewater drainage will be suitable. Of course the Water Corps may have a different view and I also need to check the Building Code of Australia (BCA) Guidelines.

Multiple HEPA Filters. Again after stakeholder engagement it was found that Vetwest are wishing to apply to the Australian Veterinary Association (AVA) to seek accreditation of their hospital accreditation scheme. The Vetwest proj mgr stated that under the AVA’s standard they required all air-conditioned spaces where animals are present to be HEPA filtered. It was evident in the mtg that they didn’t actually know how this worked as they were talking about mixing normal supply air and HEPA filtered air in the same space – which obviously negates the very clean air provided by the HEPA filters. What we did know was that just like in a human hospital the surgery room needs to be supplied by HEPA filtered air but I don’t think other areas do. To confirm I researched the AVA standards and found nothing relating to HEPA filtration at all so posed the question to one of their standards testers – I’m awaiting a reply.

NDY’s Concept Design

With these answers outstanding I cracked on and came up with a concept mech (air-conditioning) layout. I split the space into four zones and plan on using 4 No. Packaged DX Units (yet to be specified). These DX units will be mounted on the roof (where there’s plenty of space) and consist of ridged ducting for the main run with flexible ducting to each supply air grille. Figure 1 shows the draft concept design. This along with a Consultant’s Advice Note (CAN) explaining our justifications for the system type will be finished off and sent to the MC for comment before Christmas.

Post Leave Continuation

On my return from leave and after consultation with the MC over our concept design I will then begin the detailed design. This will initially consist of using a software package called Trace which gives you heat load calculation so I can then size my packaged units. I’ve had a quick play with it already and it’s very similar to Hevacomp but with more experience I’ll try and draw out some more detailed comparisons. Then I’ll have to size all the ductwork to achieve the correct flow rates etc that will lead to cost planning. At the moment the MC has quoted AUD $55k for 3 No. units and our 4 No. Packaged DX Units is looking around the AUD $70k mark. I will then move on to the hydraulic system, mainly consisting of a reticulated Oxygen supply and Suction system.

Project Reflection

Being part of the Interiors/Tenancy Section means that I will hopefully have a number of short-term design projects to PL on. This will provide me with a good basis for reflection and help steer subsequent projects in order to build on my professional development and focus on any outstanding UK-SPEC requirements.

Figure 1. NDY Concept Mech Layout

This just leaves me to say I won’t be blogging for about 4 weeks as I’m now on Christmas leave…have a Merry Christmas and a Happy New Year!