Attachment point elements

Attachment point elements (ATTA) are multi-purpose utility components that you insert into branches for many uses.

Note:
In earlier versions of the product, ATTAs were used as pipe support elements, but this has since been superseded by the latest MDS applications. Although the new applications no longer use ATTAs for pipe supports, most of the original attributes and functionality remain available.

The main attribute that controls the function of an ATTA is the ATTA Type attribute ATTYPE. This controls how an ATTA is represented on an isometric drawing as shown below:

ATTYPE settings and purpose

The ATTYPE attribute supports the following settings:

ATTAs add split points and notes to isometrics. They provide Pipe Supports, Insulation Boundaries, Flow Arrows, and links to floor and wall penetrations. The Pipe Stress interfaces use ATTAs for Forces and Moments.

Spec break(SPKBRK) controls whether an ATTA breaks a straight tube.

If SPKBRK = True, the ATTA is treated as an inline component: it appears in the tube and has arrive and leave tube lengths.

If SPKBRK = False, the ATTA can be positioned anywhere and has zero tube length on either side.

You can position an ATTA outside the branch geometry. For example, to add a note to a valve handwheel, place an ATTA at the valve’s P3 point and set AATYPE to CCNN. To avoid a dotted line between the previous component and the ATTA, set the special attribute SPKBRK to False, which makes the ATTA offline. SPKBRK = False is the default for new ATTAs and allows them to break the standard geometry rules.

List-order issues can occur if you insert a component near an ATTA with SPKBRK = False, because the ATTA’s position is not considered within the branch. To avoid this, you can temporarily set SPKBRK = True so the ATTA are used for relative positioning.

To prevent this in the applications, the ATTABREAK ON command temporarily switches all ATTAs to SPKBRK = True while you insert components, then reverts them when complete using ATTABREAK OFF.

ATTY settings and uses of ATTAs

Support ATTAs

Support ATTAs mark the position of a support on a pipe. Its use is deprecated because MDS support application uses internal references for supports.

ATTY type Unset

ATTY type Unset is the default type of support ATTA. It marks the position of a support on the pipe. They can be positioned at the intersection of projected centerlines, for elbows and bends.

ATTY type Hang

ATTY type Hang are used in the Hangers and Supports application to indicate where a hanger type support attaches to a pipe or component. They function like ATTY type Unset ATTAs but with connection references set to a hanger element.

Comment ATTAs

Comment ATTAs add a drawing note with a leader line to a position on a pipe, for a floor penetration note. They have ATTY set to CCCC. If the point is not dimensioned. For example, if it lies in the tube,it will output additional dimensions to the ATTA position.

To position the ATTA within a previous component, connect it in list order after the component, then set its position or move it by the required distance along p-arrive. The data consistency checking generates an error if TOL ATTACHECK OFF is not set.

Comment - Not Dimensioned

CCNN add a drawing note with a leader line to a position on a pipe, for example, paint color note. The ATTY are set to CCNN, and are not dimensioned.

Isometric Flow Arrow

FLOW are used to position inline flow arrows in tube. They have ATTY set to FLOW. The arrow is not dimensioned, but its location on the tube reflects its 3D position.The flow runs from head to tail when the branch FLOW is in the default forwards direction, and from tail to head when the branch FLOW is backwards.

Isometric Sheet Split Position

SSSS define where an isometric are split onto the next sheet. They use two ATTY settings depending on the iso type: XXXX for standard isometrics and SSSS for system and trim isometrics. These ATTA types can be mixed within a branch and operate according to the generated iso type. IsoDraft repositions split points when a more logical break exists nearby. For example, a Tee with a Flange welded to P3, and a Gasket and Valve connected to the Flange. If a Split ATTA is placed between the Tee and the Flange, IsoDraft splits the pipe at the natural break created by the Flange.

Insulation Limit Personnel Protection (INPP)

INPP defines the start and stop points of insulation on the isometric. The insulation specification note is shown at the start point only, to avoid duplication at the end.

Floor or wall penetration location

ATTY PENI are located where a pipe passes through a floor or wall. The 3-way component connection reference for the third p-point.(CREF) attribute links the ATTA to a FIXING element within the penetrated object, for example, panel, wall, floor. The ATTAs are created with the Pipe Penetration app in the Piping application.

ATTY and shop attributes iso output for different drawing types

The highlighted items show differences between iso drawing types.

Note:

An offline ATTA generates a data consistency error if TOL ATTACHECK OFF is not set. If TOL ATTACHECK OFF is set no check is performed on the ATTA’s orientation or position.

Supports on tube are shown with a symbol, but supports on components are not.

Comment ATTAs must lie on the centerline of the pipe.

The FLOWARROWS INLINE ON command must be used for flow arrows to be plotted for tube.

For Non Iso pipe Sketches all attas are dimensioned as part of the branch and Penetration, insulation and hanger ATTAs are added to the MTO.