Egypt Engineering Consultant Mechanical key terms

The method of summing all sensible and latent heat entering a conditioned space from conduction, solar radiation, occupants, lighting, equipment, and infiltration to size air-conditioning equipment and air distribution.

The ratio of useful cooling or heating delivered by a refrigeration or heat pump cycle to the energy input consumed, expressed in consistent units; higher values indicate a more efficient machine.

A chart plotting refrigerant pressure against enthalpy that shows the evaporation, compression, condensation, and expansion stages of a vapour-compression cycle, used to calculate capacities, power, and COP.

Superheat is the temperature of vapour above its saturation point at a given pressure; subcooling is the amount liquid is cooled below saturation. Both are used to verify charge and expansion-valve operation.

A modulating valve that controls refrigerant flow into an evaporator by sensing suction-line temperature and pressure, maintaining a set superheat so the evaporator is fully used without liquid carryover to the compressor.

The number of times the total air volume of a room is replaced in one hour; used for ventilation design, contaminant dilution, and infiltration estimates.

The proportion of total heat gain that changes moisture content (latent) versus dry-bulb temperature (sensible); it determines required apparatus dew point and coil selection.

A graphical representation of moist-air properties including dry-bulb and wet-bulb temperature, humidity ratio, enthalpy, and specific volume, used to plot air-handling processes and coil performance.

The resistance to airflow within a duct system measured as pressure, used to select fan performance and to apply the equal-friction or static-regain duct sizing methods.

A controlled pressure difference between adjacent spaces, maintained by supply and exhaust air balance, to keep clean areas positive or contaminated areas negative relative to their surroundings.

An engineered combination of smoke barriers, exhaust, pressurisation, and controls designed to keep escape routes tenable and limit smoke spread during a fire.

A dedicated pump, with driver and controller, that boosts water supply pressure to sprinkler and standpipe systems so design flow and pressure are met during a fire.

The minimum water flow rate per unit area, applied over a stated design area, that a sprinkler system must deliver for a given hazard classification.

The categorisation of occupancy by fire risk and fuel load (for example light, ordinary, or extra hazard) that sets sprinkler density, spacing, and water supply requirements.

A pressure surge caused by rapid changes in fluid velocity when a valve closes or a pump stops, producing noise and possible pipe or fitting damage; controlled by arrestors, slow-closing valves, or surge tanks.

A dimensionless number expressing the probable drainage or supply demand of a plumbing fixture relative to a baseline fixture, used to size pipes and stacks.

The water depth in a plumbing trap that blocks sewer gases from entering a building; it must be maintained within specified limits to avoid siphonage or evaporation.

An energy statement for steady, incompressible flow along a streamline relating pressure, velocity, and elevation, widely used to analyse pipe flow, pumps, and flow measurement devices.

A method of calculating head loss in pipes from friction factor, length, diameter, and velocity head; the friction factor depends on Reynolds number and relative roughness.

A dimensionless ratio of inertial to viscous forces in a flow, used to classify flow as laminar or turbulent and to select the correct friction correlation.

The absolute pressure head available at a pump suction above the liquid vapour pressure; insufficient NPSH causes cavitation, so it must be checked against the pump's required value.

Relationships showing how pump flow, head, and power change with impeller speed or diameter, used to predict performance when a pump is trimmed or its speed varied.

An electronic controller that varies motor speed by adjusting supply frequency and voltage, commonly used on pumps and fans to match output to demand and save energy.

A networked control system that monitors and commands HVAC, lighting, and other building services through controllers, sensors, and a supervisory interface, often using open protocols.

An open data-communication protocol for building automation and control networks that allows equipment from different manufacturers to interoperate over a common network.

A project delivery method in which the owner engages a designer, then awards construction to the lowest or best bidder, with the designer administering the contract during construction.

A priced schedule listing measured quantities of work items by description and unit, forming the basis for tendering, valuation of progress, and cost control.

A formal instruction, issued under the contract, changing the scope, quantity, or timing of work; it adjusts the contract price or period and must follow the agreed procedure.

A percentage withheld from each payment certificate and released at stated stages or after the defects liability period, providing the employer security for incomplete or defective work.

A standard form of contract for construction works designed by the employer, setting out obligations, payment, variation, and dispute procedures commonly adapted in Egyptian projects.

The ranked order of risk-reduction measures: eliminate, substitute, engineer controls, administrate, and use personal protective equipment, applied to reduce hazards to the lowest practicable level.

A formal written authorisation confirming that specified precautions are in place before high-risk work such as hot work, confined-space entry, or energised electrical work begins.

Entry into an enclosed or poorly ventilated space where hazardous atmospheres or engulfment may occur, requiring testing, ventilation, attendant supervision, and rescue arrangements before and during work.

A professional obligation to inform the client promptly of risks, errors, or unsafe conditions discovered in the work, even where this may affect the consultant's own fee or reputation.

A situation where a consultant's personal, financial, or other interest could improperly influence professional judgement; it must be disclosed and managed or avoided.

Liability cover protecting a consultant against claims for financial loss arising from negligent design, advice, or supervision, usually required as a condition of appointment.

The national code series issued by the Housing and Building National Research Center setting minimum requirements for ventilation, air conditioning, and energy use in buildings in Egypt.

The national code governing fire prevention, means of escape, fire detection, and suppression requirements for buildings in Egypt, issued under the Housing and Building National Research Center code series.

The national code specifying design, materials, and installation requirements for water supply and drainage systems in Egyptian buildings.