- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 25 Sep 2020
Technical drawing pen sizes
Technical drawing pens follow the same size-ratio principle as A series paper sizes, that is, an aspect ration of 1:√2, with the progression proceeding by folding the preceding size in two. When an A size piece of paper is folded in two it retains its proportions.
This means for example that after drawing with a 0.35 mm pen on A3 paper and reducing it to A4, you can continue with the 0.25 mm pen. (ISO 9175-1).
 Related articles on Designing Buildings Wiki
Featured articles and news
A look at the Government's strategic approach.
Steps to help reduce the spread of infection inside buildings.
This social media-centred hobby can be both dangerous and illegal.
Millwork wall treatment with a long and illustrious history.
HSE introduces cumulative exposure calculator.
The Edwardians and their houses.
Cut off from civilian life for over 900 years.
Gaining green support from the carbon giants.
Medieval passageways with spiritual, transport and economic purposes.
Organisation receives accreditation from Investors in People.
Click the button to subscribe.
Communicating the right information at the right time.
Materials can take on different properties to control heat and glare.
Challenges in the construction sector and beyond.