Andrews Fasteners - FAQ - Frequently Asked Questions
Andrews Fasteners Limited
0113 246 9992
+44 (0) 113 246 9992

FAQ

Frequently Asked Questions (FAQ)

EN 14399 Pre-load bolt assemblies

Should preloaded assemblies be assembled with lubrication?

According to standard requirement, during assembly you should not use any additional lubrication apart from that originally supplied.

BS EN 14399 standard is leaving a clause, that additional lubrication should be used if it is subject to supplier recommendation.

Andrews Fasteners BS EN 14399 Assemblies are supplied to k-Class k0 and are offered pre-lubricated.

We are supplying lubricated parts of the assembly. Lubricated parts are used where due to surface coating, maximum tension needs to be controlled to prevent seizure.

On assemblies BS EN 14399 k-Class K1 and K2 additional lubrication would modify the values of kand invalidate the BS EN 14399-2 test results. In that situation, additional lubrication shall not be used.

What is the difference between HR and HV bolt assemblies?

HR (British/French) bolt

The British/French approach following BS EN 14399-3 and BS 4395 is to use thick nuts and long thread lengths in the bolt assembly to obtain ductility predominantly by plastic elongation of the bolt. The longer thread length is necessary to ensure that the induced strain is not localised. These bolts are relatively insensitive to overtightening during preloading although suite control is still important. Furthermore if severely over-tightened during preloading the ductile failure mode of the bolt assembly is predominantly by bolt breakage, which is readily
detectable.

HV (German) bolt

The German approach following BS EN 14399-4 and DIN 6914 is to use thinner nuts and shorter thread lengths to obtain the required ductility by plastic deformation of the threads within the nut. In Germany, the HV bolt assembly is used in both preloaded and non-preloaded applications and it can be argued that in the event of failure by thread plastic deformation the assembly still acts as a non-preloaded assembly. These assemblies are more sensitive to over-tightening during preloading and therefore require more site control. If severely overtightened during preloading the mode of failure by plastic deformation of the engaged thread of the bolt assembly offers little indication of impending failure.

Read more: Steel Industry Guidance Notes: Standard for Preloadable Bolts

What does the HR & HV symbols mean?

HR should stand for High Resistance and HV for Hochfeste Bolzen mit Vorspannung (in English is high resistance bolts for pretension). The second is an official description, and they should serve the same purpose.

Should higher grade nuts be specified for use with galvanized or sherardized set screws and bolts on CE approved assemblies?

To accommodate the thickness of zinc it is normal practice to over-tap the nut thread. This operation reduces the strength of the nut and the overall strength of the nut and bolt assembly.

To improve the strength of the assembly manufacturers use either a thicker nut (increasing the number of threads between the nut and the bolt in the assembly) or a higher grade nut.

BS EN 15048-1: To achieve full tensile resistance, hot dip galvanized assemblies can require special measures, see EN ISO 10684, Annex F.

EN ISO 10684, Annex F: Strength of hot dip galvanized bolt or screw and nut assemblies.

b) Nuts manufactured with thread tolerance class 6AZ in accordance with ISO 965-5.

To archive full assembly strength with nuts tapped oversize to thread tolerance class 6AZ two options may be considered:

1) Fit the bolts and screws with nuts of one property class higher, i.e. bolt or screw of property class 8.8 with nut of property class 10, etc.

2) Using Style 2 nuts – thicker nuts instead of Style 1

Thicker nuts are not generally available and therefore it is normal practice for manufacturers to fit a higher grade nut.

The following are recommendations regarding higher grade nuts:

BS EN 15048 – Non-preloaded bolting assemblies

  1. Property class 8.8 bolts, assembled with property class 10 nuts
  2. Property class 10.9 bolts, assembled with property class 12 nuts*

*) EN ISO 10684, Annex F is only recommendation for consideration. There is nothing against of using same grade of nut as grade of bolt (i.e. Gr 10.9 bolt with Gr 10 nut), considering, that bolt and nut passing assembly test at specified value.

BS EN 14399 – Preloaded bolting assemblies

  1. Property class 8.8 bolts, assembled with property class 8 nuts. In this option the nuts are supplied in accordance with BS EN 14399-3 for hot dip galvanizing and have higher hardness limits and a different tolerance class to self-colour property class 8 nuts to BS EN 14399-3
  2. Property class 8.8 bolts, assembled with property class 10 nuts
  3. Property class 10.9 bolts, assembled with property class 10 nuts. The grade 10 nuts according to BS EN 14399-3 have been developed to gives sufficient strength after over-tapping

You can read more about this matter in BCSA memorandum No 191-12.

Can Pre-load (HSFG) assemblies be de-assembled once they have been assembled?

Due to safety reasons and according to BS 4604 Part 1

“If after final tightening a bolt or nut is slackened off for any reason, the bolt, nut and washer shall be discarded and not re-used.

In accordance to EN 14399

If the assembly has been tightened to the minimum force – 70%, assembly cannot be re-used.

Is two threads protruding through a pre-load fastener enough?

Overal recommendation is to have minimum 1 (one) thread above unloaded face of the nut, and minimum 4 (four) threads before shank of the bolt and the nut.

 

Please also refer to your Quality Document QCD 04 regarding to Bolt lengths (grip lengths) for preload fasteners.

What is the minimum thread length on preload bolts?

The minimum thread length is calculated strictly according to EN 14399-3 for preload bolts – System HR and EN 14399-7 for preload countersunk head bolts – System HR.

In calculation, you need to consider standard reference thread length (b), minimum length of the shank – un-threaded part of the bolt, and distance from head  of the bolt till first full thread.

To help with that, we have created two useful calculators:

In any doubts, please contact our Quality Department.

Can Pre-load bolt assemblies (HSFG) be used on painted or galvanised surfaces?

Due to compression ability of paint, galvanising coating and other types of surface protections it is required that places of joints are cleaned from any coating before installation. After the installation process, depending on the type of coating of the assemblies the whole surface can be further covered to restore  corrosion protection in joint places.

EN 15048 Non pre-load bolt assemblies

Should higher grade nuts be specified for use with galvanized or sherardized set screws and bolts on CE approved assemblies?

To accommodate the thickness of zinc it is normal practice to over-tap the nut thread. This operation reduces the strength of the nut and the overall strength of the nut and bolt assembly.

To improve the strength of the assembly manufacturers use either a thicker nut (increasing the number of threads between the nut and the bolt in the assembly) or a higher grade nut.

BS EN 15048-1: To achieve full tensile resistance, hot dip galvanized assemblies can require special measures, see EN ISO 10684, Annex F.

EN ISO 10684, Annex F: Strength of hot dip galvanized bolt or screw and nut assemblies.

b) Nuts manufactured with thread tolerance class 6AZ in accordance with ISO 965-5.

To archive full assembly strength with nuts tapped oversize to thread tolerance class 6AZ two options may be considered:

1) Fit the bolts and screws with nuts of one property class higher, i.e. bolt or screw of property class 8.8 with nut of property class 10, etc.

2) Using Style 2 nuts – thicker nuts instead of Style 1

Thicker nuts are not generally available and therefore it is normal practice for manufacturers to fit a higher grade nut.

The following are recommendations regarding higher grade nuts:

BS EN 15048 – Non-preloaded bolting assemblies

  1. Property class 8.8 bolts, assembled with property class 10 nuts
  2. Property class 10.9 bolts, assembled with property class 12 nuts*

*) EN ISO 10684, Annex F is only recommendation for consideration. There is nothing against of using same grade of nut as grade of bolt (i.e. Gr 10.9 bolt with Gr 10 nut), considering, that bolt and nut passing assembly test at specified value.

BS EN 14399 – Preloaded bolting assemblies

  1. Property class 8.8 bolts, assembled with property class 8 nuts. In this option the nuts are supplied in accordance with BS EN 14399-3 for hot dip galvanizing and have higher hardness limits and a different tolerance class to self-colour property class 8 nuts to BS EN 14399-3
  2. Property class 8.8 bolts, assembled with property class 10 nuts
  3. Property class 10.9 bolts, assembled with property class 10 nuts. The grade 10 nuts according to BS EN 14399-3 have been developed to gives sufficient strength after over-tapping

You can read more about this matter in BCSA memorandum No 191-12.

Tightening of non-preloaded bolts

Customers very often asking for torque figures for installation of non-preloaded bolt assemblies. Due to nature of this type of product, assemblies for non-preload connections, there are no torque figures available.

There are various guidances available to calculate theoretical torque figures, but following EN 1090-2 (pt. 8.3), tightening of non-preloaded bolts shall be conducted as follow:

EN 1090-2:2008+A1:2011
The connected components shall be drawn together such that they archive firm contact. Shims may be used to adjust the fit. (…)

Each bolt assembly shall be brought at least to a snug-tight condition, with special care being given to avoid over-tightening especially short bolts and M12. The tightening process shall be carried out from bolt to bolt of the group, starting from the most rigid part of the connection and moving progressively towards the least rigid part. To archive a uniform snug-tight condition, more than one cycle of tightening may be necessary.

NOTE 1 (…)
NOTE 2 The term “snug-tight” can generally be taken as the achievable by the effort of one man using a normal sized spanner without an extension arm, and can be set as the point at which a percussion wrench starts hammering.

For more details please refer to a full version of the standard.

CE Marking

What type of products can be CE marked?

Only products covered by harmonised standards can be CE marked.

In the construction fasteners industry, products that are covered by harmonised standard and can be subject to CE marking are to EN 14399-1 (Pre-loaded assemblies) standard and EN 15048-1 (Non-preloaded assemblies).

European Union is publishing in Official Journal list of standards that are laying down harmonised conditions for the marketing of construction products. This list can be found on EUR-Lex website.

Listed standards are subject to law requirement for CE marking under Construction Products Regulation 305/2011 (CPR) with further amendments.

Can product to DIN standard be CE Marked?

Only product covered by harmonised standard can be CE marked.

In EN 15408:2007 version, only products under EN/ISO standard can be subject for CE Marking.

DIN standard is a German national standard and unless it is international / european standard (EN/ISO) and approved by the European Union as a part of harmonised standard, it cannot be used for CE marking purposes.

A list of harmonised standards for CE Marking, under Construction Products Regulation (CPR) is published as a the Official Journal of the European Union (OJEU) and can be found here.

In new release of EN 15048:2016, limited number of product can offered CE Marked to the national standard like DIN or BS. For availability please contact our Quality Department.

Do bags/boxes have to have CE labels on them?

According to Construction Products Regulation (CPR) for CE Marking, CE Labels can be supplied on bags/boxes or with Quality Documents (Test Certificate or Declaration of Performance).

According to British Constructional Steelwork Association (BCSA) recommendation on their published and widely used by many customers Model Specification for the Purchase of Structural Bolting Assemblies and Holding Down Bolts CE Label shall be supplied on bags/boxes.

The decision as to where the CE mark is placed depends on whether the product is a single or extended delivery lot.

Assemblies k-Class K2 to BS EN 14399 must have CE Mark on the bag/carton box.

Assemblies to BS EN 15048 single delivery lots shall have the CE mark on the bag/carton, while extended delivery lots may have the CE mark on the documentation.

Can bags be split and then re-labelled as CE approved?

According to the CEN consultant, CE mark cannot be copied when product is split into smaller batches by a distributor who is not certified under FPC. They must retain evidence of the CE mark of the original batch together with the Declaration of Performance (DOP); they are permitted to copy the DOP and must provide a copy with each sub-batch they supply.

What is DOP?

DOP in full name means Declaration of Performance. It is a document that the manufacturer of the product should supply with every CE approved product in line with the requirements of the CPR (Construction Products Regulation).

The DOP contains information about the manufacturer, the construction product/s to be CE

Marked; the products intended use/s and the declared essential performance characteristics

of the product.

DOP can not be supplied for items that are not covered by CE marking requirements.

Further information is available in BCSA memorandum 90-13.

Please also visit our page with DOP for products offered by Andrews Fasteners Limited and released to the market.

Can holding down bolts (foundation bolts) be CE marked?

Currently, Holding Down Bolts doesn’t fall into Construction Product Regulation standards and they cannot be CE Marked.

Holding Down Bolts are manufactured in accordance with BS 7419 (British Standard). This standard is not a harmonised standard like EN/ISO, that will allow them to be CE marked.

More about this you can read in BCSA memorandum No 17-14.

In new edition of EN 15048:2016 (after standard will become harmonised), holding down bolts can be considered for CE marking after initial testing and suitability test in accordance 5.2. d) of EN 15048-2:2016.

For availability, please speak with our Quality Department.

Coating

What is the life time of galvanising coating?

Typical calculating lifetime of Hot Dip Galvanising coating is set to 20 years average, but this is based on many various like humidity, temperature, environmental impact etc.

If you require to calculate coating lifetime for your localization, please ask a question to Galvanising Association or visit their website for more details.

Why does galvanizing coating look different?

You may noticed, some products after hot dip galvanization (HDG) coating, even in the same facility using the same process may look different from others. It can be noticeable that some of the product will be much brighter and other much darker.

There is nothing wrong with the product nor with the coating and any difference will depend on the product steel.

Coating thickness and content of silicon in steel may cause different appearance on the finished product.

Please refer to this article for more details: The HDG Coating (galvanizeit.org)

Installation

What is a single lap joint according to EN 1993-1-8:2005, 3.6.1.?

A single lap joint is a joint with two plates connection with bolts.

In the case of clause 3.6.1(10) which concerns a single lap joint with a single row of bolts the bolts require two washers because as the plates are pulled apart the connection bends and the head/nut tries to pull through the plate.

Packing

Do bags/boxes have to have CE labels on them?

According to Construction Products Regulation (CPR) for CE Marking, CE Labels can be supplied on bags/boxes or with Quality Documents (Test Certificate or Declaration of Performance).

According to British Constructional Steelwork Association (BCSA) recommendation on their published and widely used by many customers Model Specification for the Purchase of Structural Bolting Assemblies and Holding Down Bolts CE Label shall be supplied on bags/boxes.

The decision as to where the CE mark is placed depends on whether the product is a single or extended delivery lot.

Assemblies k-Class K2 to BS EN 14399 must have CE Mark on the bag/carton box.

Assemblies to BS EN 15048 single delivery lots shall have the CE mark on the bag/carton, while extended delivery lots may have the CE mark on the documentation.

Can bags be split and then re-labelled as CE approved?

According to the CEN consultant, CE mark cannot be copied when product is split into smaller batches by a distributor who is not certified under FPC. They must retain evidence of the CE mark of the original batch together with the Declaration of Performance (DOP); they are permitted to copy the DOP and must provide a copy with each sub-batch they supply.

Which identification mark is used by Andrews Fasteners?

Andrews Fasteners, as well as production factory AndFast Malaysia are using as an identification mark on their product as follow:

  • Bolts – FAST
  • Nuts – FAST (EN 14399) and A (EN 15048 and others)*
    • For products manufactured starting from January 2016, each main components will retain FAST as a marking relating to manufacturer Andrews Fasteners / AndFast Malaysia;
  • Washers (where applicable) – FAST or none, where marking is not required.

Until stock least, products can be offered with markings previously used by company like: AND. and AF

If any concerns, please do not hesitate to contact our Quality Department.

Steel

Is steel recyclable?

Unlike most other construction materials steel can be recycled indefinitely without loss of property or performance. This is referred to as multicycling. It means steel always has a value, which guarantees that virtually none is ever disposed of to landfill. The multicycling of steel is a self-sustaining system that predates modern appreciation of environmental issues and would continue in the unlikely event that they should ever lessen in importance.

You can read more on BCSA memorandum No 244/12.

Is steel construction sustainable?

Steel is arguably the most sustainable of the major structural materials. It has numerous sustainability benefits, which are guaranteed to be realised whenever steel is used. They include: low waste, flexibility, offsite manufacture, speed, resource efficiency, adaptability, demountability, long lasting appeal, safety, reusability and recyclability. These inherent characteristics result in many social, environmental and economic benefits to satisfy sustainability’s ‘triple bottom line’.

More information about sustainability of the steel you can read in BCSA memorandum No 243/12.

What does the term “Secondary Steelwork” mean?

There is no generally accepted definition for secondary steelwork.

In the first interpretation the definitions given in clauses 3.7 of BS EN 10225 may be used as a reference:

Clause 3.7 Secondary elements
‘elements of minor importance, failure of which would be unlikely to affect the overall integrity of the installation’.

More you can read on BCSA memorandum No 158-12.

What is the difference between J2 and JR? Can they be used as substitutes for each other?

J2 and JR refer to the material’s sub-grade – its fracture toughness – which is measured in
joules of a material’s toughness at a particular temperature.

J2 is a material with a minimum of 27 joules at -20C while JR is a material with a minimum of 27 Joules at +20C (room temperature).

JR material is normally used in an internal environment whereas a J2 is for external use.

If J2 is required you must not substitute JR.

Test Certificates

Why is there no elongation, impact, reduction of area on some of Test Certificates?

Test certificates need to be in accordance to BS EN 10204 and include results for required characteristics as a minimum. According to standard, products need to fully comply with requirement regarding to elongation, impact and reduction of area, but results do not need to be included on test certificate.

EN 10204 doesn’t state what figures need to be supplied on test certificate and leave this open for agreement between purchaser and supplier.

Our company can obtain this figures from our factory/manufacturer archives on request, prior to purchase order.

Can Andrews Fasteners offer 3.2 certification?

Our company can offer in cooperation with independent body Lloyd’s Register Energy “intent of” 3.2 Certification.

“Intent of” 3.2 Certification includes inspection of the material in the same or a similar manner as on manufacturers site.

For more information about availability please refer to article issued by Lloyd’s Register.

If your queries have not been answered, please contact Andrews Fasteners Quality Department and we will try to help.

%d bloggers like this: