| A |
What is acoustic engineering?
The purpose of acoustic engineering is to minimise the noise output of building services installations whilst limiting the impact on the function of the systems. John Packer Associates work in conjunction with industry experts Cole Jarman Associates: specialists in acoustic design so that customers are provided with quality, cost effective results.
What are air diffusers?
These provide a way of distributing air around an occupied space. Air diffusers are the visual components of air conditioning/ventilation systems. They present themselves in a variety of forms including wall/ceiling grilles, slot and ceiling diffusers. Selection is critical to provide functionality without noise or draughts.
What is air change rate?
The quantity of air supplied to a space, expressed in terms of the number of times the total volume of air in the space is replaced in a specific period of time, typically one hour.
Top |
| B |
What are building services?
Services such as lighting, heating, ventilation, air conditioning, public health systems and lifts which, in commercial buildings, typically account in total for 30-40% of total construction costs.
What are BMS controls?
The Building Management System in a building plays a vital role in the prevention of energy waste and reducing the environmental impact of the building. The purpose is to regulate the performance of systems to meet operational environmental requirements in accordance with the design intent. Typically, a number of controllers are employed, each controlling an item of plant. The controllers communicate with each other and with a central supervisor over a local area network (LAN). The system manager is able to control the entire BMS from one point.
What is a BREEAM Rating?
A BRE initiative in which credits are awarded to a building in terms of management, energy use, health and well being, pollution, transport, land use, ecology, materials and water according to its performance. A set of environmental weightings then enables the credits to be added together to produce a single overall score. The building is then rated on a scale of PASS, GOOD, VERY GOOD or EXCELLENT, and a certificate awarded that can be used for promotional purposes.
Top |
| C |
What are chilled beams and chilled ceilings?
Chilled beams cool the air within them causing it to fall gently into the occupied area below. They comprise long rectangular units containing a finned tube through which chilled water is pumped. Chilled ceilings provide a combination of radiant and convective cooling to the space below. Both provide a quiet, draught free operation and the advantages of chilled ceilings is that they can be accommodated in very shallow ceiling voids, and are very low maintenance.
What is CHP?
Combined Heat and Power. Offers a highly economic method of providing heat and power from a single plant. Typically an engine drives an electricity generator to provide power for the building. Waste heat from the cooling water and exhaust is recovered to provide heat for heating or hot water.
What is a central plant?
The siting of plant items such as boilers, chillers air handling units in a centralised plant room/area to serve a building from a common point.
What is constant volume air conditioning?
Provides a fixed volume of air at a temperature and humidity determined by the conditions of the space being served. They are therefore not generally suitable as the primary air conditioning system for buildings with multiple zones as each zone will have varying cooling/heating requirements. An example of where this may be found are operating theatres in hospitals.
CCTV systems?
Local cameras, monitoring and recording facilities for security purposes.
What is Computational Fluid Dynamics (CFD)?
CFD provides a way of predicting what will happen when fluids flow. In terms of building services fluid flow is generally the heating, cooling or ventilation of occupied spaces. Knowing how these fluids such as air flow and what will be their quantitative effects on the solids with which they are in contact assists building services engineers and architects to provide comfortable and safe human environments by predicting how a building and its systems will behave before it is designed in detail. CFD uses a computer to solve the relevant science-based mathematical equations, using information about the proposed projects.
What are condition surveys?
These may be called for by a building occupier to provide comprehensive information on the current state of a building and its services or by a client considering the purchase or leasing of a building. The building services consultant will be required to provide clear and concise information on the condition of services, short and long term maintenance needs, and potential ongoing costs.
Top |
| D |
What are Downdraughts?
Downward moving air caused by room air coming into contact with a cold surface such as a window. The cool air sinks and can create a draught at mid and low level. Modern windows provide high levels of insulation, and downdraughts now pose less of a problem.
What is a decentralised plant?
Plant items located at strategic points throughout the building.
What is displacement ventilation?
Cool air is supplied at a low velocity from a low level wall mounted or floor mounted ventilation terminal. Natural convection causes upward air movement, where warm air is then collected by a mechanical ventilation system at ceiling level. They provide excellent air quality and thermal comfort and are energy efficient. They are often used in conjunction with chilled ceiling/beam air-conditioning systems.
Top |
| E |
Energy Performance Certificates
An Energy Performance Certificate (EPC) provides information on the energy performance of a building. The EPC will give the building a grading ranging from A to G (‘A’ being very energy efficient while ‘G’ is inefficient). It must be accompanied by an advisory report giving recommendations for cost-effective actions to improve the rating.
JPA can now offer an EPC Assessment Service; the asset ratings of buildings are calculated using IES VE software, which is also used for assessing compliance with Part L of the Building Regulations.
What are energy audits?
Energy Audits are the appraisal of the energy consumption of a building compared against the norm for a building of that particular type. Should it be found that the energy performance varies significantly from what might be expected, methods to improve its performance, together with the results that may be expected and anticipated costs are established for consideration.
Top |
| F |
What is façade engineering?
Façade engineering is becoming increasingly important for all professions involved in the design and construction of buildings. Façade design offers the best opportunity to improve the quality and comfort of buildings through the use of better materials and processes, intelligent design and the development of intelligent facades. Façade engineering offers the challenge of marrying engineering requirements with the need to achieve buildings of good appearance.
What are fan coil units?
There are generally two types; overhead units and those situated under windows. A typical fan coil unit comprises a fan, heating coil, cooling coil, and air filter all housed in a metal casing. The fan draws air across the heating and cooling coils, and the newly cooled/heated air is discharged into the occupied space. Fan coils produce quick responses to changes in temperatures and are ideally suited to buildings with multiple zones with high demands.
What are false ceilings?
A suspended ceiling below the structural slab to give a void that can be used for services distribution, such as for ventilation ductwork. Sometimes called the services zone.
What are feasibility studies?
Feasibility studies are carried out at the front end of a project to determine whether a client has the wherewithal to proceed with a project that is proposed. A study may include physical restrictions of a given site, costs, planning issues and the potential demand for a building of the type proposed.
What is free cooling?
Cooling that can be obtained without operating mechanical plant, for example by using outside air directly when it is at a low enough temperature.
Top |
| G |
What are gas suppression systems?
Systems that employ compressed gas as a fire extinguishing medium. Most commonly modern systems employ a mixture of inert gases which are introduced into the protected space in sufficient quantities to extinguish a fire, without putting at risk the life of the occupants. Generally used in higher risks and higher value spaces, such as computer server rooms and spaces that are unoccupied or permanently out of sight.
What is geothermal heating?
There is a large amount of heat just below the earth's surface and this geothermal energy can be extracted for use in generating electricity or in heating systems. There are two methods of extracting the heat: Aquifers; heat is extracted through deep naturally occurring ground waters and Hot dry Rocks; two holes are drilled from the surface of the earth, and water is then pumped down one, circulated through the naturally occurring fissures and returned to the surface via the second borehole.
Top |
| H |
What does HVAC stand for?
Heating, Ventilation and Air-Conditioning
What is heat recovery?
It is the recovery of heat for use that would otherwise be disposed of.
Top |
| I |
What is infiltration?
Air that enters a building through cracks and gaps in the building fabric due to temperature difference and/or wind. This air can provide some ventilation but is uncontrolled and unreliable. Infiltration can also contribute to building heat loss during winter and heat gain in summer. Building Regulations require that buildings are constructed to be as airtight as practicable.
Top |
| L |
What are life safety systems?
Life safety systems are any active system designed to protect property, equipment, as well as people's lives. Life safety systems include security and alarm systems, fire suppression systems, audio and visual systems (such as closed circuit television and intercom systems), access control systems, fire detection and alarm systems and nurse call systems. Since many facilities require more than one of these types of systems, a combination of all of these devices can be incorporated into an overall life safety system.
What solutions do you provide for listed buildings?
Generally the main driver for work in listed buildings is for the services installations to be as invisible as possible, yet provide the correct environment for the occupants and the protection of the building fabric. This is generally achieved by careful attention to detail and a three dimensional consideration of where equipment and distribution networks are to be housed.
What is low temperature hot water?
Hot water circulated within a system close to atmospheric pressure at a temperature of usually less than 90 degrees celsius.
What is LV distribution?
Low Voltage distribution is the useful electrical power distributed around the building, generally considered at 400 volts and below.
Top |
| P |
What are pre-acquisition surveys?
These are important engineering services reports for clients anticipating the purchase or sale of investment properties, the auditing of maintenance quality, or simply to ascertain maintenance and repair requirements.
The surveys are produced in order that the potential purchaser, vendor, or building manager will have a professional indication of the condition of all of the services and systems, which constitute a hidden and potentially costly element of any building's assets.
What are passive systems or measures?
Systems or measures which achieve a reduction in the heating or cooling load without the use of mechanical systems.
What are photovoltaics?
Solar radiation can be converted directly into electricity using photovoltaic (PV) cells. The technology was first utilised for powering satellites but is now increasingly being used to meet electricity requirements around the world. Photovoltaics are semi conductors which generate electricity when exposed to light these are called PV cells. Interconnected cells encapsulated into a sealed unit producing a useful voltage are called PV modules.
What is passive solar design?
The use of the fabric and orientation of a building to capture the sun's energy without causing problems of overheating. It thus reduces the need for artificial heating, cooling and lighting. For example the orientation of the building should be such that it allows solar radiation to heat the space through the glazed areas whilst at the same time minimising heat losses from shaded facades. Glazing should be arranged to increase the amount of daylight available, so reducing the need for artificial lighting. Natural ventilation can be maximised by allowing solar heated air to assist natural convection by using the 'stack effect', therefore minimising the need for mechanical ventilation.
Top |
| R |
What is re-circulated air?
Often more air is required to heat or cool than is needed to provide ventilation (for breathing and odour dilution). The excess can sometimes be re-circulated providing a very effective method of heat recovery. Re-circulation may not be possible when the air is contaminated with dangerous or unpleasant pollutants such as cigarette smoke.
What is relative humidity?
A term often used to specify the internal design condition for humidity within a space. A ratio, often expressed as a percentage, indicating the humidity of the air. It gives a measure of how humid the air is compared to the maximum it could possibly be.
What are room based heat pumps?
Individual units which can be floor standing or concealed in a void such as a ceiling. These are all linked by a piped water circuit that runs around the building. Each unit operates independently and is able to heat or cool the air in the immediate area.
What is resultant temperature?
A temperature often used to specify a design condition for a space, it combines air temperature, surface temperature and air velocity into a single index
What is a riser?
AA shaft providing vertical distribution of services within a building or to carry services between floors.
What are renewables?
Renewable energy describes energy flows that occur naturally and repeatedly in the environment, eg from the sun, wind and the oceans, and from plants and the fall of water. It also includes energy available from wastes and the emerging clean technologies eg fuel cells. Viable renewable energy sources include: wind power, hydroelectric power, wave and tidal power, photovoltaics, active solar heating, passive solar heating, municipal and general wastes, landfill gas, geothermal energy, agricultural and forestry wastes and energy crops.
Top |
| S |
What is solar gain?
Heat gain caused either by sunshine directly entering a space or by sunshine incident on building fabric which absorbs the heat and then transmits it to the space.
What are split systems?
Made up of two basic components; indoor room cooling units and outdoor refrigeration units. These units are linked by pipes that transport refrigerant between them, and provide a relatively cheap way of providing cooling (and heating) to a space.
What is stratification?
A vertical temperature gradient in a fluid such as water or air put to good use in displacement ventilation.
Top |
| T |
What is thermal response?
Our in-house specialists can carry out detailed dynamic predictive modelling of a proposed scheme to ‘test-drive’ the design before detailed design commences. These tools are useful in demonstrating:
- The appropriateness of the natural ventilation strategy
- The true benefit of passive design measures
- Services requirements for Mechanical Engineering Design
- How to improve the energy efficiency of the building
- The impact of the proposed development on existing buildings
- Materials selection
- Carbon emissions of the building
- Potential for renewable energy
We use Thermal Modelling techniques that enable us to determine the thermal performance of a building at the design stage.
What is thermal response?
The time taken for a system or emitter such as a radiator to warm up. Also the time taken for the fabric of the building to respond to a change in temperature.
Top |
| V |
What are validation reports?
Regular checks should be undertaken to ensure that building and services systems remain within the operational state required by the occupier. To achieve these regular tests of building services should be set up. The requirement for periodic system validation will depend on a number of factors from the building's use to commercial considerations.
What is variable refrigerant flow systems (VRF/VRV)?
A type of air conditioning system that can provide cooling only or simultaneous heating and cooling. In simple terms, it is a more sophisticated split system that employs a single external unit and multiple room units. Ideal for application in offices and hotels.
What is variable air volume air conditioning (VAV)?
An all air system which can satisfy the individual cooling requirements of multiple zones, typically within office buildings. This is achieved by supplying air at a constant temperature from central plant to one or more VAV terminal units in each zone and varying the amount of supply air depending on the demand. Space requirements are high with this type of system.
Top |
| W |
What are workplace quality surveys?
The surveys carried out by specialist organisations to consider the physical characteristics of a work space and the experience and attitude of its occupants. Surveys of this type may unearth long term or unidentified problems which are impacting on occupant health or productivity.
Top |
| Z |
What is zoning?
The division of a building into a number of distinct zones for the purposes of system control.
Top |
