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SCI CONNECT – February 2021

A new SCI publication (P424) has been published which provides design guidance on the fire resistance of light steel framing. P424 contains guidance on how light steel framed buildings should be designed and detailed to provide fire resistance in accordance with the Building Regulations. The guidance addresses the criteria that need to be considered and explains how these can be achieved with light steel framing. It also includes information on fire testing and how to use the data obtained from fire tests in design.

Fire resistance is an important part of the design for any building and since the Grenfell fire disaster the question of fire safety has been heightened. SCI has been working with members of the Light Steel Forum and other industry experts to update design guidance on the fire resistance of light steel framing which is well established as a construction system for medium-rise residential and mixed-use buildings. Light steel framing has gained a market share partly because one of its benefits is that it is non-combustible and does not add to the fire load of the building.

Steel has well-known properties at elevated temperatures and comprehensive design data is presented in BS EN 1993-1-2 and formerly in BS 5950-8. Cold formed steel has slightly reduced strength retention properties at elevated temperatures compared to hot-rolled steel sections because of the influence of local buckling of its thin profile. Nevertheless, Class 4 sections (such as cold formed steel sections) retain over 50% of their nominal yield strength at 500°C.

Light steel framing differs from hot-rolled steel frames in that it is a planar construction system. The walls and floors are protected by layers of Type F gypsum-based boards or similar boards. In the last 3 years, an unprecedented number of loaded fire tests have been performed by light steel framing and plasterboard suppliers to satisfy 60, 90 and 120-minutes fire resistance requirements for loaded walls and floors.

A fire test on a loaded wall or floor is generally performed using a light gauge steel section with the highest sensible load that can be applied by the test house. Temperatures are measured on the steel sections at a number of positions, so that the critical temperatures can be related directly to the load that is applied for the particular wall build-up. With this test information, the design of a wall or floor with thicker steel sections or with a different height or span from that tested can be calculated using the method developed by SCI and presented in P424.

SCI publication P424 is available in hard copy from mid-March and is already available for SCI Members to download on Steelbiz. P424 includes:

  • Detailed design information on the application of the Building Regulation requirements to light steel framing, including requirements for fire testing.
  • Construction practice and detailing of light steel frames and their interfaces with other materials.
  • A set of typical generic construction details for light steel framing in terms of design for fire resistance.
  • Calculation methods which may be used to extend the tested fire performance of a light steel wall or floor construction to a wider range of design parameters.

SCI would like to thank the members of the Light Steel Forum for their assistance with P424 and we look forward to working on our next area of technical development together.


P424 Fire Resistance of Light Steel Framing

Contents
Featured Article
High Strength Steel
SCI Assessed for Typhoon Bolt Caps
Recorded Webinar on R&D Tax credits
Members Advisory Desk
SCI Advisory Q&A
SCI Webinars, Courses
& Events
Members in the News
New Members
Publications
 
SCI Courses
Steel Connection Design Designing in Stainless Steel - Member Webinar
16 Mar 2021 12:30–13:30
Steel Connection Design Portal Frame Design On-line Course
4 sessions
24, 25, 31 Mar
& 1 April
View all courses
High Strength Steel

During January and February four webinars were held about high strength steels (HSS), covering their production, properties, availability, design to the Eurocodes and introducing the new SCI Publication P432 HSS Design and Execution Guide.

As part of the EU Research Fund for Coal and Steel project STROBE (Stronger Steels in the Built Environment), the performance of HSS has been studied, in particular the potential for plastic design, the stability of beams and columns and the dynamic response of HSS floor beams. The results of this research were also presented at the webinars.

Michael Sansom (SCI) spoke at the final webinar and presented a number of comparative designs for different types of buildings to identify where HSS can lead to significant savings in terms of weight, carbon and cost. The use of HSS can be beneficial in the following designs:

  • Primary beams with some end fixity to the major axis of columns, with span/depth ratios of less than 20 so that serviceability does not control,
  • long-span primary beams with large web openings in which the perforated web may gain from being higher strength,
  • deep heavily loaded transfer beams that support columns from a number of levels above and which create column-free space below,
  • columns in high-rise buildings, where a reduction in column size can be beneficial.

Between 250 and 350 people attended each webinar which shows there is a genuine interest in the use of HSS. At the final webinar, a panel of experts answered questions from the audience on a wide range of issues.

The webinar presentations and recordings can be accessed from this web page. Two design tools are also available here - one is an online design tool for HSS beams in accordance with the Eurocodes, which covers the design of both HSS plate girders and also hybrid plate girders where a lower strength steel is used for the webs. The other is a downloadable floor vibrations analysis tool and can be used to calculate the critical response factors for a floor system by performing an eigen value analysis using finite element methods.

The detailed findings of the STROBE project will also be available from this web page at the end of March.

High Stregth Steel
SCI Assessed for Typhoon Bolt Caps

SCI have reviewed the independent test evidence for Typhoon Bolt Caps, which are used to protect bolt heads and nuts in steel connections. Bolt Caps are an alternative to other forms of fire protection. The tests show that the Bolt Caps may be used to protect bolts for up to 180 minutes in temperatures up to 1200C, keeping the temperature of the bolt below 550C. Typhoon Bolt Caps are now listed on the SCI Assessed website.

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Recorded Webinar on R&D Tax credits

ForrestBrown, who have helped SCI and some of SCI's Members to claim R&D tax credits for a number of years, hosted a webinar on the 23rd February to present some important changes to the way businesses access R&D tax relief.

To clamp down on the rise in spurious R&D claims, HMRC scrutiny is at an all-time high and it has shifted its approach to administering R&D tax relief. To raise awareness of this issue, ForrestBrown shared best practice guidance on how you to add value to your overall claim.

If you missed the webinar please watch again here.

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Members Advisory Desk Service email alerts.

The new Advisory Desk service emails sent this month included;

Advisory Desk Note - AD 433
Dynamic modulus of concrete for Floor Vibration Analysis

Advisory Desk Note - AD 459
Shear resistance of stainless steel fixings

If you are an SCI Sole Trader or Corporate Member and not receiving these emails alerts go to the SCI Information Portal and in your Profile click on notifications/alerts and select the notifications you require.

All the Advisory Desk Notes and Questions and Answers together with other technical resources are all available at all times on the SCI Information Portal.

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SCI Advisory Questions and Answers

For SCI Sole Trader and Corporate members, SCI offers support through our Advisory Desk Service. For questions asked which we feel are pertinent to the wider member audience we publish anonymously the questions and answers.

Where some questions relate to SCI Publications we publish the question and answers in Connect.

This month our published question is about; Buckling of arches

Question: When considering the in-plane buckling of arch members, how can the buckling length be determined?

Please see the answer to this Advisory Question/Answer - Ref No AD_QA_7155-21 and all Advisory questions on the SCI Information Portal.

The Advisory Desk Service is for SCI Corporate and Sole Trader Members advisory@steel-sci.com | +44 (0) 1344 636525

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SCI Courses, Webinars and Events

SCI Online Training Courses

On-Line Portal Frame Design Course

This online course is delivered in 4 sessions
Part 1 - 24 March 2021
Part 2 - 25 March 2021
Part 3 - 31 March 2021
Part 4 - 1 April 2021

Time: 10:00-12:00

This course aims to provide in-depth coverage of the major issues surrounding the analysis, design and (crucially) the detailing of portal frames. The course covers frame design to BS EN 1993-1-1. The course assumes that bespoke software will be used in many designs, but aims to present the background structural mechanics so the principles are understood, such that a manual design could be completed.

The objectives of this course are to:

  • Introduce a range of practical issues which have a critical impact on the design of portal frames;
  • Discuss the loading in portal frames, from BS EN 1991;
  • Discuss the preliminary sizing of portal frames;
  • Clarify the Eurocode provisions for:
    • In-plane frame stability (the significance of second order effects);
    • Member stability and restraints;
    • Haunch resistance;
    • Serviceability checks;
    • The UK provisions for buildings close to a boundary.
  • Comment on the design of portal frame connections; Exercises and examples will be included.

Who should attend?

If you are a structural designer involved with conceptual design, detailed design or checking of portal frames. This course is for you.

Member Rate - £250.00
SCI Non-Member - £330.00

For more information and to book this course click here.


Light Gauge Steel Design Course

Next SCI Member webinar is;

Designing in Stainless Steel
16 March 2021
Time: 12:30-13:30

This webinar introduces the use of stainless steel in structural applications. Topics covered include grade selection and design of members and connections in accordance with Eurocode 3.

Register here to view this webinar

For a list of webinars, on-line public courses visit the
SCI Information Portal

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Members in the news

Mitigating Risks in Residential Buildings

Light steel structures fully comply with the requirements of the Building Regulations and leading warranty providers. Performance covers structural, fire, acoustics, thermal, airtightness, weathertightness, shrinkage, programme and accuracy. Here Steve Thompson Managing Director for light steel frame specialists, EOS - considers reducing the fire load to mitigate risk.

As a proven and versatile technology, light steel frame construction offers numerous, cost, programme and safety benefits for residential developers. Light steel frame has a high strength to weight ratio, making systems the lightest material for a load-bearing frame whilst still maintaining a robust structure. The longevity light steel frame structures attain combined with the inherent value of an asset that can be recycled or reused at end of life - means that steel is not a cost, it is an investment.

Damage to a structure during construction through moisture or fire leads to potential delays to contract, losses and expensive remediation works or even complete loss of the structure. A key advantage of light steel frame when compared to timber frame structures is fire performance and protection from weather during the construction process.

Read More

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New Members

SCI would like to welcome new members;

JIG Consulting Engineers Northern Ltd

Grade Consulting Limited

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Benefit Costs
SCI Publications

Our bookshop is once again open. For any hard copies of SCI Publications visit the SCI WebShop.

Fire Resistance of Light Steel Framing (P424)

Fire Resistance of Light Steel Framing (P424) This New publication provides guidance on how light steel framed buildings should be designed and detailed to provide fire resistance in accordance with the Building Regulations. The guidance addresses the criteria that need to be considered and explains how these can be achieved with light steel framing.

High Strength Steel and Execution Guide (P432)

High Strength Steel and Execution Guide (P432) The purpose of this guide is to present comprehensive guidance on when and how the benefits of steel with strengths from 420 to 700 MPa can be exploited in practical design situations in the construction industry.

Fire Resistance of Steel Sections Galvanized to EN ISO 1461 (P429)

Fire Resistance of Steel Sections Galvanized to EN ISO 1461 (P429) This design guide provides tables to calculate fire resistances and maximum fire exposure periods for galvanized steel beams, composite beams, columns, and plates in tension, according to the Eurocodes and the UK and Irish National Annexes.

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