Miami Stainless - Wire Balustrade Regulations

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YOUR GUIDE TO THE BCA BALUSTRADE REGULATIONS (Updated May 2010)

Background: The BCA 2010 wire balustrade regulations have followed on the same from the BCA 2009. The BCA 2009 regulations introduced some significant changes to the wire balustrade regulations. These changes gave consumers more choice on wire sizes, types and spacings available when constructing a balustrade; this fortunately has made it allowable for D.I.Y. type systems to have wider spacing between wires and posts making the use of stainless steel wire balustrades economical than has previously been available.

Below is a simple rundown of the BCA 2010 regulations, if you are unsure or require further information please call us on 1800 022 122 for further information and advice.

Getting Started: One of the first steps when planning your balustrade is to have an understanding of the different wire types that are available, the most common wires used for balustrades are 3.2mm 1 x 19, and 3.2mm 7 x 7 wire (also described as 3mm wire). 3.2mm refers to the diameter of the wire, and 1 x 19, and 7 x 7, refer to the construction or lay of the wire, i.e.1 x 19 wire is made up of 1 single wire with 19 strands in it, where as 7 x 7 wire is made up of 7 wires with 7 strands within each wire, below is a diagram showing the make up of each of these wires.

Will The the regulations apply to my balustrade? It may be possible that your wire balustrade will not need to comply with BCA regulations; below are some common situations and how you can deal with them.

COMMON SITUATIONS

My deck has a drop off less than 1 metre to the area below, what do I need to do? If the bottom of your deck is less than 1 metre off the ground, then the regulations will not apply to you. It is over to you to decide the most appropriate level of safety, wire spacing, and how many support posts you use on your balustrade.

My deck has a drop off more than 1 metre to the area below, what do I need to do? You will need to fit your wires and posts according to BCA Regulations. Below is the applicable table for doing Horizontal wire balustrades

BCA 2010 TABLES In order to satisfy the BCA 2010 regulations for a horizontal wire balustrade your system must either meet the tension requirements set out in Table D2.16a; or must not exceed the maximum deflections set out in Table D2.16c.

BCA 2010 TABLE D2.16a WIRE BALUSTRADE CONSTRUCTION – REQUIRED TENSION FOR STAINLESS STEEL HORIZONTAL WIRES

			Clear distance between posts (mm)

			600	800	900	1000	1200	1500	1800	2000	2500
Wire dia. (mm)	Lay	Wire spacing (mm)	*Minimum required* tension in Newtons (N)**
2.5	7x7	60	55	190	263	415	478	823	1080	1139	X
		80	382	630	730	824	1025	1288	X	X	X
		100	869	1218	1368	X	X	X	X	X	X
2.5	1x19	60	35	218	310	402	585	810	1125	1325	X
		80	420	630	735	840	1050	1400	1750	X	X
		100	1140	1565	X	X	X	X	X	X	X
3.0	7x7	60	15	178	270	314	506	660	965	1168	1491
		80	250	413	500	741	818	1083	1370	1565	X
		100	865	1278	1390	1639	X	X	X	X	X
3.0	1x19	60	25	183	261	340	520	790	1025	1180	X
		80	325	555	670	785	1015	1330	1725	1980	X
		100	1090	1500	1705	1910	X	X	X	X	X
4.0	7x7	60	5	73	97	122	235	440	664	813	1178
		80	196	422	480	524	760	1100	1358	1530	2130
		100	835	1182	1360	1528	1837	2381	2811	3098	X
4.0	1x19	60	5	5	10	15	20	147	593	890	1280
		80	30	192	300	415	593	1105	1303	1435	1844
		100	853	1308	1487	1610	2048	2608	3094	3418	3849
4.0	7x19	60	155	290	358	425	599	860	1080	1285	1540
		80	394	654	785	915	1143	1485	1860	2105	2615
		100	1038	1412	1598	1785	2165	2735	X	X	X
Notes:
1	Lay = number of strands by the number of individual wires in each strand. For example a lay of 7x19 consists of 7 strands with 19 individual wires in each strand.
2	Where a change of direction is made in a run of wire, the tensioning device is to be placed at the end of the longest span.
3	If a 3.2 mm wire is used the tension figures for 3.0 mm wire are applied.
4	This table may also be used for a set of non-continuous (single) vertical wires forming a balustrade using the appropriate clear distance between posts as the vertical clear distance between the rails.
5	X = Not allowed because the required tension would exceed the safe load of the wire.
6	Tension measured with a strain indicator.

Download printable Version of Table 2.16a

BCA 2010 TABLE D2.16c WIRE BALUSTRADE CONSTRUCTION – MAXIMUM PERMISSIBLE DEFLECTION FOR STAINLESS STEEL WIRES

		Clear distance between posts (mm)
		600	900	1200	1500	1800	2000
Wire dia. (mm)	Wire spacing (mm)	Maximum permissible deflection of each wire in mm when a 2 kg mass is suspended at mid span
2.5	60	17	11	9	8	8	8
2.5	80	7	5	5	5	X	X
3.0	60	19	13	8	7	7	7
3.0	80	8	6	6	5	5	5
4.0	60	18	12	8	8	7	7
4.0	80	8	6	4	4	4	4
Notes:
1	Where a change of direction is made in a run of wire the 2 kg mass must be placed at the middle of the longest span.
2	If a 3.2 mm wire is used the deflection figures for 3.0 mm wire are applied.
3	This table may also be used for a set of non-continuous (single) vertical wires forming a balustrade using the appropriate clear distance between posts as the vertical clear distance between the rails. The deflection (offset) is measured by hooking a standard spring scale to the mid span of each wire and pulling it horizontally until a force of 19.6 N is applied.
4	X = Not allowed because the required tension would exceed the safe load of the wire.
5	This table has been limited to 60 mm and 80 mm spaces for 2.5 mm, 3 mm and 4 mm diameter wires because the required wire tensions at greater spacings would require the tension to be beyond the wire safe load limit, or the allowed deflection would be impractical to measure.

Download printable Version of Table 2.16c

So What Works Best when installing horizontal wires?

3mm 1 x 19: We have found that when using 3.2mm 1 x 19 wire having your posts spaced at 1200mm with your wires at 80mm spacing is the easiest way to ensure that the tension required for your balustrade will be easily achievable and will pass inspection.

3mm 7 x 7: We have found that when using 3.2mm 7 x 7 wire having your posts spaced at 1500mm with your wires at 80mm spacing is the easiest way to ensure that the tension required for your balustrade will be easily achievable and will pass inspection.

This means that a balustrade with wire support posts every 1200mm or 1500mm, and a top rail height of 1 metre (960mm under the top rail) will require 11 runs of wire when spaced at 80mm with a tension that will be easily achievable.

Please note: The above recommendations are the opinions of Miami Stainless derived from their own testing and experience and are intended as a guide only. In some situations it may be more suitable to use different wire or posts spacing. Please call us on 1800 022 122 if you are unsure or you require any advice.

My deck has a drop off more than 4 metres to the area below, what do I need to do? In this situation you are not allowed to use horizontal wires and instead they will need to be vertical, this process can become slightly more complicated, please contact us on 1800 022 122 for advise on how to design your vertical balustrade.

PLEASE FEEL FREE TO CALL US ON 1800 022 122 IF YOU HAVE ANY FURTHER QUESTIONS REGARDING THE BCA REGULATIONS