Laserfiche WebLink
� � ` <br /> �..,;:,. <br /> � . , <br /> � � ' BUILDING PLAIV(VING <br /> � �; <br /> ���� �.� , <br /> _ � �� ��� �This required depth shall continue for at least 3/$ inch on both sides of the profile. See Commentary Figure � <br /> � � �� � (10 mm) to a level that is not less than 13/ inches (45 R311.7.8.3(2)for the limitations of a Type II handraiL � <br /> � `� nun below the tallest ortion of the rofile. The mini- <br /> � � ' ) P P R311.7.8.4 Exterior woodlplastic composite� handrails. <br /> � � �� inum width of the handrail above the recess shall be 11/ Wood/plastic composite handrails shall comply with the pro- <br /> �inches(3�mm)to a maximum of 23/4 inches (70 mm). visions of Section R5073. <br /> � � � �� Edges shall have a minimum radius of 0.01 inch (0.25 <br /> � � mrn). �.•Handrails made of wood/plastic composite materials <br /> �` � " must meet the requirements for installation, labeling <br /> _�. <br /> � :� :•To be effective, a handrail must be easily grasped by and compliance with ASTM D 7032 stated in Section <br /> � � the vast majority of users. If it is too {arge, it is difficult R507.3, in addition to the general requirements for <br /> � � ;� ' for a user to get a strong enough grip to provide the handrails in this section. <br /> � ` � needed support. If it is too small the fingers wrap and <br /> � ` � �, �"��� interfere with the thumb and palm and cannot close in � <br /> �� �� � �� a sufficient grip. For this reason Type I rails have min- � <br /> � I �,, imum and maximum perimeters to restrict their use to HANDRAIL PERIMETER>6�/4 IN. <br /> �� the effective size range. Tests have proven it is bene- <br /> , �, � ficial to have graspable recesses for the fingers and �1�!4 IN.To 23/4 IN.� <br /> .� � � ,.opposing thumb such that wider and taller shapes <br /> � ' � �; can provide graspability comparable to rails within the , <br /> � ,� � Type I size range limitations. The Type II handrail � <��IN. <br /> �� ,. �code provides specifics to the location and depth of � ! <br /> ' the recess as it relates to the variables of crown '� <br /> � � �� >13/4 IN. <br /> �� � y�, height and width to ensure the design is of a grasp- <7I8�N. <br /> � � � able shape. The mountings of smaller profiles can �� � <br /> � . cause interference, as well. Care should be taken to ".'�'��" � <br /> � � �p minimize the interference caused by brackets and � � >_3/$�tv. <br /> � ��_ �� � . <br /> � ,,baiusters supporting profiles that require the bottom 1 <br /> � mounting surface to be grasped. <br /> � '� � GRASPABLE FINGER RECESS AREA <br /> � � u The code specifies that the handrail be either Type IS REQUIRED ON BOTH SIDES—►� �–>_5/�6 IN. <br /> �� ����� � '"�I or Type II, or be equivalently graspable. A Type I <br /> � � _� can be either circular or noncircular in shape. See <br /> Commentar Fi ure R311.7.8.3 1 for exam les of <br /> � � Y g � � P For SI�. 1 inch=25.4 mm. <br /> Type 1 handrails. <br /> � ,� . � Figure R311.7.8.3(2) <br /> A Type II handrail has a penmeter larger than 6 /4 <br /> � � �� � TYP�II H,4NDRAIL <br /> � � �,� � "' inches (160 mm) with graspable finger recess area <br /> � � <br /> � �� <br /> .� � <br /> � � � �� � ' � �� � HANDRAIL THAT IS NOT CIRCULAR <br /> � ;� � ; � MUST HAVE A PERIMETER OF 4 IN. <br /> _. , ,' <br /> � � � MW/6�/4 IN. MAX WITH A MAXIMUM <br /> CROSS SECTION DIMENSION OF <br /> � HANDRAIL WITH CIRCULAR 2�/4 INCHES <br /> � �:` . � �1�/a W.MIN/2 IN. MAX � � , <br /> � � DIAMETER I= 1 l2IN.--�— <br /> � •`' �' � � <br /> � �, � � <br /> � <br /> �i� � �� ` � 1�/2 IN. <br /> '� <br /> �: � g <br /> , <br /> � � v <br /> � �; 0.01 IN. RADIUS� <br /> � �;� � <br /> �� ^�— <br /> � �� <br /> � CIRCULAR HANDRAIL NONCIRCULAR HANDRAIL <br /> � � � . �. - <br /> i� � �For Si: 1 inch=25.4 mm. � <br /> � � � � '� Figure R311.7.8.3(1) <br /> � �� �� � � � TYPE 1 HANDRAIL <br /> �` ��' � " <br /> : � �� � <br /> �,' ;�2a12 I�TERNATIONA!RESIDENTI,AL CODE°COMMENTARY 3-97 . <br /> � � ;. � <br /> �.. . <br /> �� � �� , � <br />