Internal Door Surround Acoustic Design: Seals, Glazing and Room-to-Room Performance

Walk through a doorway between two occupied rooms and listen: what you hear is rarely the wall. The separating element of a doorway is the frame-and-leaf system around the opening — the head, the two jambs, the reveal lining and the threshold — and the quietness of the room you are leaving is decided almost entirely by how well that fixed enclosure seals around the leaf when it closes. In specification language, that fixed enclosure is the Internal Door Surround, and on any project where room-to-room noise is a live issue, it is the component most likely to be under-designed, under-sealed and under-inspected.

For the purposes of this guide, an Internal Door Surround is the complete fixed framing installed around an internal door opening: the head member above the opening, the two jambs either side, the internal reveal or lining that bridges frame to wall, and the bottom channel or threshold detail into which the leaf rests. The leaf is the moving element; the surround is the stationary one, and acoustically it is the more important half. A leaf transmits sound, a surround bypasses it — and bypass is what makes a quiet door loud. Every open gap around the leaf is a tunnel, and a tunnel is open from the moment the seal stops touching.

This guide treats the Internal Door Surround as an acoustic design problem rather than a finish product. It works through the pathways sound actually takes through an internal doorway, the perimeter seal systems that close those pathways, the door leaf and its build-up, glazed panels and their safety glazing obligations, the hardware that keeps the leaf aligned against its seals, the floor and ceiling junctions that complete the perimeter, and the privacy, fire and accessibility checks that attach to specific projects. It closes with installation discipline, the honest boundaries of acoustic testing, a maintenance routine that keeps a sealed detail sealed, and answers to the questions designers and owners ask most often. Where a claim matters, it is tied to the framework that governs it: the National Construction Code, published by the Australian Building Codes Board, and the Australian and New Zealand standards that sit beneath it. And it shows how a dedicated Australian and New Zealand manufacturer, Meichen International Windows & Doors (MC Windows), applies the same sealing discipline across its certified aluminium window and door systems, at mcwindow.com.au.

The Internal Door Surround as an Acoustic Assembly

The useful mental model for an internal doorway is not a door with a seal, but a sealed perimeter with a door in it. Airborne sound — speech, music, the hum of plant — meets the doorway and does not choose to go through the leaf, the glass or the wall. It takes every open path in the assembly: around the edges of the leaf, under the bottom edge, around the frame where it meets the wall, and anywhere the lining was left unfinished. The acoustic performance of the finished doorway is set by the weakest of these paths, which means a heavy leaf behind a leaking perimeter will perform exactly as badly as the leaking perimeter performs.

This is why the surround, not the leaf, is the acoustic decision. The leaf can be adjusted; the geometry of the fixed frame, the seal channels it carries, the threshold detail it establishes and the way it is joined to the wall are set at design and installation time and stay set for the life of the building. The NCC, in its sound insulation provisions for separating elements in the building classes where they apply, frames the obligation in terms of performance between spaces; the doorway is where that performance is most often lost, because the doorway is the one element in the separation that people move every day. The room-to-room target lives in the building’s own requirements, and the Internal Door Surround is the component the design team must actually make work.

How sound gets through an internal doorway

Two mechanisms need separating, because they are managed differently. The first is transmission through the elements: sound passing directly through the leaf material, the glazing and the frame sections themselves. This is a mass-and-damping problem, and it is largely decided by what the leaf is made of and what is glazed into the panel. The second is bypass around the elements: sound travelling through any open route in the perimeter and arriving in the receiving room without ever passing through the leaf. Bypass is an airtightness problem. In practice, on a typical internal doorway, bypass dominates: a small continuous gap around the leaf can erase most of the benefit a heavier leaf would have provided, and closing the perimeter is the cheaper, more reliable lever. The design consequence is direct — spend the acoustic effort on the seals, the threshold and the reveal before spending it on the leaf.

The four bypass paths around the leaf

Map the perimeter of a closed internal door and the paths fall into four groups, all of them features of the surround and its installation:

The hinge-side perimeter — the line where the leaf meets the frame on the hinge edge. This is the path most affected by leaf drop, because hinge wear and frame twist move the whole edge against its seal.
The lock-side perimeter — the line where the leaf meets the frame on the locking edge. This path carries the most traffic force and the most seal compression, and it is where paint, grit and a poorly seated strike quietly open a tunnel.
The bottom edge and threshold — usually the loudest single path in the whole door. The threshold detail sets how closed the bottom stays through the building’s floor movement and the leaf’s daily flex.
The head and the reveal line — the frame-to-wall gap above and on both sides of the opening. This path has nothing to do with the leaf at all; it is the sound that walks around the door through the building itself, and only a properly detailed, sealed reveal closes it.

Four paths, four different failure modes, and all four are within the design and installation control of the party specifying and fitting the Internal Door Surround. That is what makes the surround a design component rather than a trade finish: each path has a named detail, a named seal and a named inspection point, and a specification that names them is a specification that can be checked on site.

Perimeter Seals: Where the Room-to-Room Difference Is Made

The perimeter seal is the working part of the acoustic system, and it is a compression system, not a glue system. A compressible seal — a gasket or brush that the leaf presses into the frame channel as it closes — only performs while it is being compressed, while it is clean, and while the geometry that loads it stays true. Design the seal for the closed position, not for the photograph.

Continuous compression around the closed leaf

The seal should run continuously around every path it is protecting: down the lock edge, across the bottom and up the hinge edge, seated in a channel that keeps it in place under repeated closing. Intermittent sealing — a seal only where a sight line catches it, or a weather-type gasket carried over from an external detail without being checked for internal compression — is the most common design error in internal doorways, because it looks finished. The channel itself is a surround feature: its depth, its position relative to the frame face, and the clearance the leaf is hung with all determine how much compression the seal actually receives on a normal close, without the door being forced shut. That clearance is a design value, not a site adjustment, and it belongs in the drawings.

What degrades a seal, and on what timescale

Seals fail in predictable ways. Compression set is the slow one: a gasket that is permanently over-compressed loses its rebound and eventually stops touching the leaf on a light close. Contamination is the fast one: paint from an adjacent coat, silicone from a tiler’s seam sealer, or polish from the first year of cleaning all stop a seal from gripping. Misalignment is the structural one: a frame fixed out of square, or a wall that has moved against a rigid reveal fill, changes the compression along the whole edge. None of these failures is visible from across the room — a door with a degraded seal closes exactly like a door with a good one. They are visible only in the receiving room, as a level of noise nobody can point at, which is why the maintenance section of this guide treats the seal line as a named inspection item rather than as part of a general “check the door.”

The slim-section argument, made by engineering

There is a persistent assumption that a slim internal frame cannot carry a serious seal system, because the section has no width to hide a gasket in. Meichen’s systems are the working counter-argument. The company positions its aluminium window and door systems as high-performance and silent precisely because the profile geometry and the sealing system are engineered together, and its air tightness performance is described as excellent specifically for acoustic and thermal insulation. In a slim section the seal channel, the leaf rebate and the compression line are designed as one geometry, so the seal works without adding visible bulk to the reveal. The practical specification consequence is that the slim look and the sealed perimeter are not a trade-off to be negotiated: the section drawing should show the seal channel and the compression detail, and if they are not drawn, they are not designed.

Door Leaves: The Moving Half of the Acoustic Detail

The leaf is the element people see, judge and open, but in the acoustic chain it is the second lever. Its jobs are to transmit as little sound as possible through its own face, to stay aligned against its seals through every close, and to be stiff enough that the forces of hardware and traffic do not distort it out of its seal line. A leaf that flexes at mid-height stops touching the perimeter seal at the middle of the long edges — the one line of the perimeter nobody looks at.

Solid, lined and glazed leaf build-ups

Internal leaves come in build-ups that differ in cost, weight and acoustic behaviour, and the choice should follow the separation target. Solid cores and heavily lined leaves carry the most mass for the least deflection; hollow cellular leaves are light and economical but need more stiffness to hold their seal line; and a glazed leaf puts a plane of glass into the leaf face, which changes both the transmission and the perimeter story because the glazing adds a bead line and an edge detail inside the leaf itself. For the high-privacy rooms a project actually has — the study that takes calls, the conference room, the consultation room, the bedroom that faces a media room — the honest answer is that the leaf build-up and the seal system have to be specified together, because a heavy leaf on a leaking perimeter performs the perimeter’s number, and a light leaf on a sealed perimeter performs much closer to its own.

Leaf alignment: the closed position is a design output

Where the leaf sits when closed — the compression on each edge, the bearing on the threshold, the pull of the lock to the strike line — is the output of the surround’s geometry, the hardware schedule and the installation all at once. A door that closes with visible effort is usually over-compressed on one edge and starved on another, and over time the over-compressed seal sets while the starved edge opens. Commercial leaves with spring closers add a force programme to the equation: the closer’s speed and holding force have to be set so the door lands on its seals rather than slams into the frame, and that setting is part of commissioning, not an afterthought. On an aluminium leaf system the advantage is consistency — the section does not creep or move with humidity, so the alignment it is hung in is the alignment it stays in, which is the quietest form of long-term behaviour a leaf can have.

Glazed Panels: Light, Sightlines and the Acoustic Trade-Off

Glazing in an internal door is a design choice that buys light, continuity and supervision — a parent seeing into a study, a clinic seeing into a room, an office staying visibly open — and it carries a cost in acoustic behaviour that should be stated in the specification, not discovered at handover. A plane of glass is stiffer than most leaf build-ups but far less massive, and the acoustic result of a fully glazed leaf depends heavily on the glazing unit, its fixing and the seal detail around it.

Double and triple Low-E units at internal positions

It is a mistake to assume that an internal glazing unit is the same product as an external one. Where a slim-frame internal partition calls for double or triple glazed units with Low-E components — the same glazing technology Meichen pairs with its thermal-break systems — the unit’s construction, its interpane spacing and its edge seal all contribute to how much sound the plane passes, and the frame channels have to be detailed for the unit’s actual weight and edge condition rather than for a single lite. The edge is the quiet-critical part: a glass edge that sits in a channel with an air path to the other side of the frame has bypassed the glass entirely. The glazing detail — channel, bead, spacer and seal — is therefore an acoustic detail, and it belongs in the shop drawing with the same status as the perimeter seal.

Safety glazing at internal door positions

Because internal glazing sits at head height in a high-traffic line, the safety glazing standards apply as firmly inside the building as outside it. AS 1288:2021, Glass in buildings — selection and installation, is the selection rulebook the NCC points to; AS 2208 carries the safety glazing requirement; and AS/NZS 4200, Glass in buildings — selection and use of glass, is the companion guide that walks the specifier through the risk zones, including internal door and adjacent glazing. In practice, toughened or laminated glass is the norm for internal door lites and sidelights rather than a preference, and the installed glass carries the marking that proves what it is. For New Zealand work the same discipline applies under the SNZ regime — Meichen’s New Zealand certification base includes SNZ TS 4211:2022 and SNZ 4223 — so a trans-Tasman project should confirm on the drawing which standard edition and which marking the glass carries.

The glazing bead line as a bypass path

Add the glazing to the list of bypass paths and the perimeter of a glazed internal door gains a fifth tunnel: the bead line where the glass meets the leaf. A leaf that seals perfectly at the frame but sits in a channel where the glass edge is open has given away a continuous line of perimeter right around the middle of the leaf. The specification answer is the same as for the frame — a continuous, compressible, drawn detail — and the inspection answer is the same too: the bead line is checked in the closed position, not on the bench.

Hardware: The Acoustic Role of Hinges, Locks and Closers

Hardware is usually specified as a mechanical schedule — hinges, lock, closer, push plate — and reviewed for strength, finish and fire compatibility. It is rarely reviewed for acoustics, even though every one of those items loads the seal system. A hinge line that carries the leaf slightly proud of its seal line has already decided the compression on that edge; a lock that pulls the leaf to a strike that is off-line has decided the lock edge; a closer set too hard has decided how the door arrives at its seals every single time. Hardware is the part of the surround system that acts on the leaf every day, and it is the easiest part to get right, because it is entirely specified before the door is ever on site.

Meichen’s supply chain note on hardware is relevant here: the company fits its systems with specialised ANZ hardware, backed by more than ten years of experience matched to Australian and New Zealand requirements. On an internal acoustic door that matters because the hardware has to do three jobs at once — carry the leaf load, set the door onto its seals, and survive the traffic — and hardware chosen for the local door sizes, fixing methods and traffic patterns is hardware that keeps doing those jobs. The specification line is short: name the hinge type and count against the leaf weight, name the lock and its strike, name the closer and its landing behaviour, and state that the closed position is to be checked against the seal line at commissioning.

Floor and Ceiling Junctions: The Rest of the Perimeter

The Internal Door Surround does not stop at the frame. Above the head and below the threshold, the acoustic perimeter continues into the wall and the floor, and sound that cannot get through the door goes where the building lets it: up into the cavity above the head, or down into the void and floor construction below the threshold. A doorway is quiet only as quiet as the junctions that complete its loop, which is why the floor and ceiling junctions belong in the door specification, not in the general wall specification.

The head junction and the cavity above

The gap between the top of the frame and the finished wall above it is a classic flanking path. If that gap is filled rigidly, it will crack with the building’s movement and open into the cavity; if it is left unsealed, it is a direct line into the wall above the door. The detail that works is a flexible, sealed joint that tracks movement without losing its seal, and a wall construction above the door that does not provide an open cavity route into the receiving room. In buildings where the NCC’s sound insulation provisions apply to the separation, the junction above the door is part of that separation, and the design team should be able to show — on the wall section, at the door — how the path is closed.

The threshold and the floor construction below

Below the door, the threshold detail has to do two jobs at once: keep the bottom seal compressed and closed, and coordinate with the floor finish on both sides. A flush internal threshold rides on top of the floor build-up, which means the floor movement, the screed tolerances and the leaf’s flex all act on the seal at the loudest path in the door. A drop or raised threshold closes the gap more absolutely but changes the floor transition, which is a live issue for accessibility, wheeled equipment and the clean line the design intent is after. The answer is a project decision, drawn on the section, checked against the accessibility requirement, and installed to a flat, level floor build-up — because a threshold installed on a sloped floor is a seal that is already half open.

Privacy, Fire and Accessibility: Project-Specific Design Checks

Three requirements attach to some internal doors and to none others, and the moment they attach they change what the surround has to prove. They are project-specific — the same surround family may carry no checks at all in one building and all three in the next — and the design discipline is to identify them early, while the detail is still cheap to change.

Privacy as a design input, not a mood

Privacy in the brief is an acoustic and a visual problem, and the acoustic half is the one that surprises owners: a door that looks closed can still carry a conversation across the room. Where the design intent is genuine acoustic privacy — a study, a media room, a consultation room — the surround should be specified with the seal system, the threshold detail and the reveal detail named, and the target should come from the building’s requirements or the owner’s brief, written down. The visual half is handled by the reveal and the finish, and by the maintenance of the seal line. Both halves belong in the same drawing set, because they are the same perimeter seen two ways.

Fire coordination, stated without invented ratings

Where an internal door is required to contribute to fire separation, the honest rule is that it is part of a tested assembly — leaf, lining, frame, hardware and seal — and the fire performance belongs to that tested assembly, not to any one element of it. The NCC and the applicable Australian fire resistance standards define what is required, project by project, in terms of the building’s classification and the element’s role. What this guide will not do is publish a fire duration for a surround or a seal system: that would be exactly the kind of invented value that the testing discipline exists to prevent, and substituting a different lining or a different seal after the assembly was tested is what breaks the performance. The check is administrative as much as technical: the assembly as installed must match the assembly as tested, and the documentation should say which one. On the Meichen side the position is stated plainly: the company is actively pursuing CodeMark certification, the highest level of Australian assessment, alongside its existing certification base — AS 2047 for windows and doors, AS 4284 for performance, AS 1288 for glass, AS 4666 for installation and AS 2208 for safety glazing, with 43 product series certified in Australia. Fire-relevant internal doors on a project are specified from that evidence base, assembly by assembly, not from a general claim.

Accessibility coordination on the threshold and the leaf

Where an internal doorway serves a public or common space, the accessibility requirements attach to the threshold, the clear passage and the force needed to operate the door, and AS 1428.1 is the Australian standard that carries the design criteria. The acoustic instinct — a tight threshold, a heavy leaf, a firm closer — pushes directly against the accessibility requirement, and the correct resolution is not to pick a side but to design the detail: a flush sealed threshold that keeps the bottom line closed without creating a step, a leaf and closer set so the operating force stays within the standard, and a passage line that stays clear. The surround is where these requirements physically meet, which is why the accessibility check belongs in the door specification, at the section, before the threshold profile is ordered.

Installation: Building the Acoustic Detail to the Drawing

Acoustic installation is the difference between a sealed perimeter on paper and a sealed perimeter in the building, and the standard that governs the discipline is AS 4666, Installation of windows and doors. The rules that matter for an acoustic internal doorway are the same rules that matter for every internal doorway, applied to the tolerances the seals need:

Frame square, reveal consistent, seals unobstructed

The frame is fixed true and level, with a consistent gap around the whole perimeter before the lining goes on, because the reveal lining is a sealing element as well as a finish. The gap is closed with a detail — a flexible sealed joint or a formed reveal profile — not stuffed with packing. Every seal channel is checked for obstruction: a paint film from an earlier trade, a silicone bead from the tiling, a chip from the floor screed — each one sits between the leaf and the seal and converts a designed compression into a designed gap. The threshold is installed on a flat, level floor build-up and checked against the leaf’s bottom edge in the closed position, with the leaf’s weight and flex in play. None of this takes longer than the alternative; it takes discipline.

The closed position, checked at commissioning

The commissioning check for an acoustic internal door is a short, specific sequence: close the door on a normal cycle and check the compression on the hinge edge, the lock edge and the bottom; check the bead line if the leaf is glazed; check the lock and strike alignment; check the closer’s landing on the seals, not into the frame; and record the result against the drawing that showed the seal line. A door that fails the check is adjusted at the hardware and the reveal, not packed under the leaf or glazed over the seal, because those fixes trade a future leak for a present convenience. Meichen’s local base runs through its Sydney partnerships, and the 20,000 square metre facility in Zhaoqing, Guangdong, is the manufacturing base behind the systems the installer is fitting — the same production discipline applied to the section that the site is checking.

Testing Boundaries: What the Standards Can and Cannot Prove

The Australian and New Zealand standards give the industry a tested-evidence system, and the useful thing about a tested-evidence system is that it has boundaries. Knowing where those boundaries are is what separates a careful specification from a confident guess.

Which test regime covers which claim

Performance testing of windows and doors — water tightness, air tightness, wind load resistance — sits under the AS 4284 regime, and the acoustic performance of building elements is tested under the AS 4284.5 regime, with the underlying measurement methods carried in the AS 1530 series. Glass selection and safety sit under AS 1288:2021, AS 2208 and AS/NZS 4200, and installation sits under AS 4666. These labels are the vocabulary a specification should use, because each one defines a tested property with a defined method, and a property tested by a method is something a reviewer can ask for evidence on. Meichen’s certification record is that vocabulary in use: 43 product series certified in Australia against AS 2047, AS 4284, AS 1288, AS 4666 and AS 2208; 13 product lines certified in New Zealand against SNZ TS 4211:2022 and SNZ 4223; and international verification from BV, CSI, NATA, AZUMA and INTERTEK, with CodeMark actively pursued as the next level.

Why a rating belongs to a specific assembly

The boundary that matters most in this guide is the assembly boundary. A tested result is the result of the exact assembly that was tested — that leaf, that frame, that seal, that threshold, that glazing unit, in that configuration. Change the seal and the result no longer describes the door; change the threshold detail and the same is true. This is why this guide will not publish a decibel figure for an Internal Door Surround, and why a specification should not quote one for a configuration it has not had tested: a number quoted for a different assembly is not a measured value, it is a guess with units on it. The correct question to put to a manufacturer is not what the rating is, but what was tested, as a whole assembly, and can the evidence for the configuration being specified be produced on request. The boundary is not a weakness of the standards; it is the whole point of them.

Maintenance: Keeping a Sealed Detail Sealed

An acoustic internal door is a maintenance item, not a fit-and-forget one, because the seal system is a compressible, contact-loaded detail in a traffic line. The programme is short, and it should be written into the building’s operations manual at handover:

Check the seal line twice a year — hinge edge, lock edge, bottom, and the glazing bead line where present. Look for paint, grit, silicone or a visible gap in the closed position; clean the line, and re-compress or replace seals that have set.
Check the closed position — the door should land on its seals without force. A door that is getting harder to close, or that closes with a slam, is telling you the alignment has moved, and the answer is the hinge and the strike, not a harder push.
Check the threshold — the floor build-up under and around the threshold is the load path for the bottom seal; a cracked or settled floor section opens the loudest path in the door long before it is visible.
Keep the hardware schedule — the hinge type and count, the lock, the closer setting. Hardware that is replaced should be replaced to the schedule, because the seal line was designed around it.

The cost of this programme is minutes per door per year, and the value is that the room-to-room performance the design team specified at the surround is the performance the building still has at year ten. It is also the reason the original specification — the seal system, the threshold detail, the reveal detail, the hardware schedule — should be in the handover file: maintenance of a detail nobody documented is improvisation.

Frequently Asked Questions

Is the Internal Door Surround the main factor in room-to-room sound control?

On a typical internal doorway, yes — the surround and its seals are usually more decisive than the leaf, because airborne sound takes the open paths around the leaf rather than through it. A heavy leaf behind a leaking perimeter performs the perimeter’s number, which is why this guide puts the seal system, the threshold and the reveal detail ahead of the leaf build-up in the order of the specification.

Can a slim aluminium surround seal as well as a heavier timber one?

A seal is a geometry and a compression, not a width, and a slim section can carry a continuous seal system if the channel, the leaf rebate and the compression line are designed together. Meichen’s systems are positioned as high-performance and silent for exactly this reason: the profile and the gasket are engineered as one detail, and the air tightness is described as excellent for acoustic and thermal insulation. The check is the section drawing — if the seal channel and the compression detail are not drawn, they are not designed.

Which standards cover the acoustic and safety performance of internal doors in Australia and New Zealand?

The performance framework sits in the NCC, published by the ABCB, with the sound insulation provisions applying in the building classes where they apply. The tested-property standards are AS 4284 and AS 4284.5 for window and door performance, the AS 1530 series for measurement method, AS 2047 for the window and door product, AS 1288:2021, AS 2208 and AS/NZS 4200 for glass selection and safety, and AS 4666 for installation. In New Zealand, the SNZ regime — including SNZ TS 4211:2022 and SNZ 4223 — carries the equivalent product and installation requirements.

Can a fully glazed internal door ever be a quiet one?

Yes, but the glass has to be part of the acoustic plan rather than an afterthought: the glazing unit’s construction and edge detail, the bead line around it, and the perimeter seal of the leaf all have to be drawn as one system. The safety side is separate and non-negotiable — internal door glazing is a risk location under AS 1288:2021 and AS 2208, so the glass is specified to the zone and marked accordingly, and the acoustic specification is written around the glass that is actually installed.

Who is responsible for the doorway’s acoustic performance — the door supplier or the building team?

The responsible party is the one who can be shown the detail. The surround supplier is responsible for the frame, the seal system, the threshold profile and the installation guidance under AS 4666; the building team is responsible for the reveal, the floor build-up and the wall construction above the head. The defect that kills the performance is usually on the interface — the reveal gap, the floor level, the obstruction in the seal channel — so the specification should name both parties’ details, and the commissioning check should be a joint one, recorded against the drawing.

What should I ask Meichen before specifying an internal door surround?

Ask what was tested, as a whole assembly, for the configuration being specified, and ask for the evidence under the relevant standard — the performance programme under AS 4284, the acoustic regime under AS 4284.5 where a measured target exists, and the installation guidance under AS 4666. Ask for the seal channel and compression detail on the section drawing, the threshold profile against the floor build-up, and the hardware schedule against the leaf weight and the traffic. Meichen International Windows & Doors has been dedicated to the Australian and New Zealand market since 2017, with 18 to 19 years of industry expertise behind it and a 20,000 square metre facility in Zhaoqing, Guangdong, and its Sydney partnerships handle the local side of the supply chain. The company’s position on the two open items is stated plainly: CodeMark certification is actively pursued, and a rating is quoted only for a tested assembly. The specifications are at mcwindow.com.au.

Conclusion: The Internal Door Surround Is the Acoustic Decision

Strip an internal doorway back to its working parts and the picture is consistent. The leaf transmits, the surround bypasses, and the room-to-room result is set by the weakest path in the perimeter — the hinge edge, the lock edge, the bottom, the head, the reveal and the bead line. The Internal Door Surround is therefore the component the design team actually controls: the seal system drawn into the section, the threshold detailed against the floor, the reveal sealed rather than stuffed, the hardware scheduled to carry the leaf onto its seals, and the floor and ceiling junctions closed as part of the same loop. Privacy, fire and accessibility are project-specific checks that attach to this same detail, and installation under AS 4666 is where the drawing becomes the building.

That is the discipline Meichen brings to the ANZ market: a high-performance, silent aluminium systems company dedicated to Australia and New Zealand since 2017, with 43 certified product series in Australia, 13 certified product lines in New Zealand, a 20,000 square metre facility in Zhaoqing and local partnerships in Sydney — and a testing culture that quotes evidence for tested assemblies and will not invent a number for the ones it has not tested. The room you are trying to quiet is on the other side of a perimeter. Design the perimeter, and the room follows.