The Additional Tools

In addition to Zebra’s Core Tools, we have created some smaller tools that cover basic building physics.

These are very simple tools and are designed mainly for teaching or student project work, but could be used by professionals that do not have access to in-house building engineering teams.

In all cases, we give the equations used, and these should match naturally with the ones used in class on in documents from organisations like CIBSE. Alongside the calculation area of each tool, there is a much larger area of explanations of the building physics which acts as a refresher or revision of the topic. This area is also laced with design tips

The additional tools of the Zebra Suite consist of the following:

Studio report

We produced a report to show how the ZEBRA tools (core and additional tools) might be used in a real studio project created by a group of students in the Department of Architecture and Civil Engineering at the University of Bath. ZEBRA was not used in their original project, so we have re-imagined the project by inserting a variety of results into their project report, based on calculations using ZEBRA. The ZEBRA sections can be easily found in the pages with a red border.

You can access the report using the following link:

ZEBRA studio report

Zebra condensation considers the risk of condensation in flat, opaque building elements, such as wall, roofs, and floors. It addresses the following concerns, based on the methods described in BS ISO13788.

• Critical Surface Humidity: I.e. the risk of mould developing on interior surfaces.

• Interstitial Condensation: I.e. the risk of moisture building up within the layers of the fabric, and causing damage to materials or even water run-off.

• Drying: I.e. whether or not the fabric will dry in the reasonable time if moisture is accidentally introduced. E.g. by rain during construction, or a plumbing leak during operation.

The following documentation is available for Zebra Condensation

Zebra daylight looks at the potential for daylight at the building and the site boundary, room daylight factors, room depth and the no-sky-line. It covers the following topics:

• Basics: Some general comments on daylighting to give context to the calculations.

• Daylight potential: where to place the building to ensure good daylight.

• Site boundary: how close to a site boundary is it sensible to developed.

• Daylight Factor: Average and working plane daylight factor calculation.

• Room depth: check to see if the back of the room will be overly dim.

• No-sky line: check to see how much of the room is exposed to direct light from the sky.

The following documentation is available for Zebra Daylight

Zebra Heatloss calculates the instantaneous heat loss (or gain) from the whole building, including the fabric, ventilation and infiltration; then looks at annual heating and cooling demand based on both the degree day and kilo-Kelvin hours philosophies. This spreadsheet also considers form factors of buildings.

The following documentation is available for Zebra Daylight

Zebra Operative Temperature estimates realistic temperature in a room based on external temperature and characteristics of heating systems.

Zebra Sound covers the speed of sound in materials, conversions between frequency and wavelength and to decibels, propagation of sound outdoors, decomposition of sound into frequencies and octaves, addition of multiple sources, A-weighting, room radius, NR curves, reverberation time, room-to-room-sound transmission, sound ingress through a facade

Zebra Sunpath plots a sunpath diagram for a point on a façade and the intensity of sunlight on it.

Zebra System Sizing sizes the heating, cooling and air handling systems in a space via the introduction of a design temperature.

Zebra U-Value calculates the U-value of a construction, including multilayer constructions and ones which include studwork or similar.

The workbook contains two worksheets: "U-values" looks at simple situations of homogenous constructions; "Non-homogenous" at more complex cases where more accurate estimates are wanted.

The following documentation is available for Zebra U-Value

Zebra Ventilation uses simple opening layouts to look at instant and annual natural ventilation and heat removal.